Optical parametric oscillators based on periodically poled MgO-doped lithium niobate (PPMgLN OPOs) are ideal sources for high-power,continuously tunable mid-infrared (MIR) light,which is attractive for applications including laser spectroscopy,atmosphere detection and MIR countermeasure. In this paper,temperature tuning characteristic of PPMgLN OPO and oscillation threshold of pulsed SRO are analyzed theoretically. An OPO with PPMgLN pumped by Nd:YAG (1064 nm) Q-switched polarized laser is reported. The oscillation threshold is 1.7 W,which is close to the theoretical result. Idler output power of 1.35 W at 3.93 μm is achieved with pump power of 12.3 W. Idler wavelength output is tuned continuously from 3.846 to 3.952 μm with temperature varied from 60 to 140 ℃,which is in accordance with the theoretical tuning curve.

The free space laser communication has advantages of large data transmission amount,high direction of transmission and high transmission security. It has become one of the developing directions of next generation optical communication technologies. The tapered semiconductor lasers are the most important optical sources in the free space laser communication. In this paper,it has introduced the structure design,output characteristics and beam quality of 808 nm tapered semiconductor lasers. The total laser cavity length is 3.5 mm (tapered single emitters consist of a ridge section with a length of 800 μm and a tapered section with a length of 2.7 mm,the tapered angle is 6°). Si and SiO2 (95% reflectivity) are deposited at the rear facet with the help of electronic beam evaporator. The front facet is coated with a single layer of SiON (<1% reflectivity).The threshold current of the device is 0.75 A. The maximum slope efficiency is 0.615 W/A. The output power of the device reaches 2 W,horizontal divergence is 3.9°,vertical divergence is 40° and M2 factor is less than 1.8. It shows the device has good beam quality.

A combination method between relative measurement and absolute measurement is presented,which obtain the distribution of optical intensity for a 1.4 kW pulsed TEA CO2 laser in the distance of 335 m. Then the results of measurements are discussed and analyzed. The experimental results show that this approach is a good and precise and considers the influence of atmosphere which is the main factor. Flat top and fragmentation come forth in the distribution of optical intensity and furthermore appears one side lobe,which has very important reference value for evaluating the tactical effectiveness and optimization design of laser system.

In frequency-modulation/continuous-wave (FM/CW) scannerless lidar system the intensity modulated (IM) laser transmitter of high-power is a key component for radar imaging. In order to realize target detection of long imaging range and high ranging accuracy,the transmitter needs to possess output optical power more than 10 W,optical modulation depth higher than 70%,better modulation linearity and radio frequency (RF) bandwidth broader than 200 MHz. This paper introduced various schemes of high-power laser modulation,including the direct modulation of diode lasers,the lithium niobate crystal bulk modulation and the combining waveguide modulated seed laser and optical amplification. Their advantages and disadvantages of schemes were analysed. Finally,the modulated lasers array based on multi-quantum well (MQW) electroabsorption modulation was put forward. As a transitional scheme,the optical modulation combining electroabsorption modulated laser and optical fiber amplification were shown in the paper.

Discharge driven continuous wave HF/DF chemical laser has been used widely in many research fields. The extensively adopted discharge scheme is high voltage DC power combined with ballast resistors,which is characterized by lower electrical efficiency,large volume and high cost,and is not convenient for use. Referring to the application of current-self-limited transformer on discharge electric gas lamp,current-self-limited transformer and selenium rectifier were used in this paper to make laser running successfully and reduce the volume of laser system significantly. This power supplication scheme is much simpler and can be applied to other discharge driven gas lasers.

The drift of zero output is the main fact to impact measurement precision of the system. The temperature and nonlinearity which effect the measuremert precision the open-loop fiber optic gyro (O-FOG) are analyzed,and a novel model is presented to compensate errors caused by temperature and scale factor nonlinearity. The model is related with three factors:operate time,temperature and input angular rate. The precision can be improved by training. Experimental results show that it can eliminate effect of temperature drift and scale factor. The precision is improved in all temperature range,which shows the scheme′s feasibility.

Residual stress is an inevitable factor in microelectromechanical system (MEMS) surface micromachining,it affects the performances of the devices. In this paper,the formulas for calculating the pull-in voltage and the stroke of an electrostatic micromirror with residual stress existed have been derived by introducing an equivalent mechanical model,and the effect of the residual stress on the eigen-frequency of the micromirror is analyzed. The result shows that the eigen-frequency increases with the residual stress. The micromirror surface profile,under different residual stress,is tested by a white light interferometer. Experimental results indicate that the residual stress makes a warp on the surface,and it declines Strehl ratio and lower the image quality.

A new manufacturing method for the pyramid sensor using mask moving lithography (MML) process is proposed. Firstly,there is one time moving mask exposure in both two orthogonal directions,and then a pyramidal structure is formed in the photoresist after development. Secondly,the structure will be transferred into the substrate of silicon. Lastly,metallization is carried out to increase the reflectivity of the pyramidal mirror. The completed pyramidal mirror has a square base of 1 mm length and mirror-like for side-facets inclined to the base at 3.7° with knife edges and sharpening tip. The sizes of pyramid tip and turned edges are both at about 6 μm ,and the root mean square (RMS) of the four mirror-like facets is approximately 77 nm.

Computer controlled optical surface (CCOS) technology is a very important method to fabricate large aspheric optical surfaces. Computer numerical controlled small tool technology is based on Princeton hypothesis. It used a small lap which travels over the work-piece surface. By accurately controlling the dwell time and other parameters,a prescribed amount of material can be removed at each point on the surface. There is the problem in the process of manufacturing. Aspheric optical elements,which fabricated using computer controlled optical surface technology,almost have medium high-frequency(≤33 mm period) errors on their surfaces,and very difficult to remove . A flexible tool is fabricated in order to deal with the problem. The transmutation of the flexible tool has been simulated. The thickness of the two kind of flexible material has been calculated by the simulation. The flexible tool had been used in the manufacture process of 420 mm f/2,paraboloidal mirror. After three hours of smoothing with the flexible tool,almost all medium high-frequency errors have been removed,and the precision of aspheric optical surface isn′t destroyed.

Computer controlled optical surfacing (CCOS) technology is a common method to fabricate off-axis aspheric mirrors,whose diameters are less than 500 mm. CCOS technology is based on Preston hypothesis. It uses a small lap which travels over the workpiece surface. By accurately controlling the dwell time and other parameters,a prescribed amount of material can be removed at each point on the surface. Considering the problem in the process of manufacturing,a best fit sphere is chosen reasonably. A computer controlled model is found,which tool path is along the contour line of sagittal surface of the off-axis aspheric mirror. The two dimensional convolution operation is reduced to one dimensional convolution. The constant-linear pressure distribution model is used to analyze the edge effect. The manufacture process of a 124 mm off-axis aspheric mirror has been simulated. The result shows that under the direction of the model,the root mean square of its surface figure error decreases from 0.018mm to λ/60 (λ=632.8 nm).

In the process of manufacturing square GRIN lens,ion-exchanging to cylindrical glass stick Tl was made by ion-exchange method at first,then square GRIN lens sample was machined. The refractive index distribution was measured by Ya-Ming interferometer method,and the aberration was measured by foursquare grid chart. The measurement results were compared with that of related reference. The results show that square GRIN lens sample manufactured by this work has smaller aberration and better imaging quality. But the maximal value of refractive index distribution is deviated from the geometric central axis of the square GRIN lens,while that is not existed in related reference. The results of this research have certain reference value and guiding significance for the development of square GRIN lens.

There are several methods for machining different kinds of off-axis parabolic mirrors. A progress based on fine grinding and computer controlled optical surfacing (CCOS) are presented in this article. Machine and grinding principle of fine grinding are introduced,also the error source and choosing the parameters for grinding are analyzed. CCOS for polishing off-axis parabolic mirror and optical testing it with interferometer are briefly introduced. An experiment on a parabolic mirror of 160 mm diameter is carried out and the obtained surface contour is 0.2 μm (perk-to-valley). The results of experiment show that fine grinding combined with CCOS is an effective machining method for off-axis parabolic mirror.

The active optical technique on traditional optical accessory especially on large aperture mirrors in order to get better surface quality and small wavefront error of the optical system is discussed. The test is based on  640 mm spherical surface,which is made of K9 optical glass. The surface quality is corrected by active controller,and the wavefront error of the system is reduced in evidence. The results show that the active optical technique can also be applied on traditional optical accessory.

Piezoelectric deformable mirrors(PDM) is a widely-used wavefront corrector in the adaptive optics which is to compensate for the wavefront aberration generated by the atmosphere turbulence in astronomical telescopes and laser communication systems. Analyzing the performance parameters of PDM,like fitting error,actuators′ number and spatial arrangement,dynamic range,we designed an experimental adaptive optic system based on 19-channel PDM. This system uses Zernike modal approach to reconstruct the wavefront and real-time control PDM to compensate three wavefront aberrations:defocus,astigmatism and coma simulated in Matlab in a negative feedback closed loop. The experimental results show that the piezoelectric deformable mirrors have good correction capability for wavefront aberration in negative feedback closed-loop adaptive optic system.

The control method of close-loop adaptive optical (AO) system with single wavefront sensor and multi-wavefront-correctors was proposed. The wave aberration was measured using single wavefront sensor. The wavefront aberrance was decomposed to lower rank wave aberrations and higher rank residual error by decoupling method and algorithm of limitative correction. In this way,different types of wave aberrations are corrected by different wavefront correctors respectively. The wavefront correctors with little elements are used to correct low spatial frequency wave aberration using Zernike wavefront modal algorithm. The wavefront corrector with more elements is used to correct the residual high spatial frequency wavefront error using direct gradient wavefront control algorithm. An adaptive optical system using a single Hartman wavefront sensor (HS) with 96 sub-apertures to control 19-element deformable mirror (DM),61-element deformable mirror and 127-element deformable mirror has been numerical simulated. It is proved that this method can improve the compensation ability of an adaptive optical system.

The semi-empirical dispersion formula was applied to analyze the mode dispersion and Cerenkov radiation attenuation characteristics of coplanar striplines on LT-GaAs substrate in the frequency domain over a terahertz range. Also,FFT was employed to numerically model the time domain propagation characteristics of ultrashort electrical pulse along the coplanar striplines on LT-GaAs substrate. The results reveal that distortion will appear in the waveform of the ultrashort electrical pulse because of the mode dispersion and Cerenkov radiation attenuation mentioned above at frequency range over THz. The shorter the width of the original pulse is,the more serious the distortion becomes. The reduction in the thickness of the LT-GaAs substrate can weaken the mode dispersion and Cerenkov radiative attenuation,and as a result,the propagation characteristics of the ultrashort electrical pulse along the coplanar striplines on LT-GaAs substrate is improved.

Silicon on insulator (SOI) provides a three-layer structure of Si/SiO2/Si,and makes it possible to achieve continuous membrane micro-deformable mirror based on deep reactive ion etching (DRIE). By using the SiO2 as the self-stop layer of dry etching,a single crystal silicon reflective mirror membrane can be readily realized with uniform and precisely controlled thickness. A process based on DRIE and anodic bonding of SOI wafer/Pyrex 7740 glass was presented,and a micro-deformable mirror with 69 actuators was fabricated and tested. The micro-deformable mirror,with an aperture of 10 mm,exhibits a working range of 4.25 μm,a PV flatness of 1.2 μm and a RMS roughness of 193 nm.

In order to improve the coupling efficiency between the single-mode fiber and the nano-silicon-wire waveguide in silicon-on-insulator (SOI),a novel tapered spot-size converter (SSC) is designed,which is constructed with a tapered silicon waveguide and an overlaid rectangular hybrid sol-gel SiO2 waveguide. Simulation analysis,which is performed with the three-dimensional beam propagation method (3D-BPM) at λ=1550 nm with semi-TE polarization,shows that the coupling efficiency can be up to 95% (loss of 0.22 dB),which is very promising for high coupling efficiency between the single-mode fiber and the nano-silicon-wire waveguide.

A novel approach to design the subwavelength metal rectangular gratings used as the polarizing beam splitters was presented. The method was based on effective medium theory (EMT) and thin film optics. The polarizing diffraction performance of subwavelength grating was analyzed by the method of rigorous couple-wave analysis (RCWA) for the wavelength of 650 nm. The numerical calculation was used to analyze the effects of the 0-order diffraction efficiency caused by the grating period,the groove depth,the incident angle and the incident wavelength. The results show that subwavelength metal rectangular grating have the characteristics of metal films with high reflectivity for TE polarization and the characteristics of the dielectric films with high transmission for TM polarization. The optimal design agrees excellently well with the results simulated by RCWA method.

Beam sampling grating (BSG) is an important optical element applied in the terminal optical system of inertial confinement fusion (ICF) drivers. It can separate a very slight part of laser energy (-0.1%) from the main beam,thus provide sampling signal for the precise diagnosis of the laser parameters. However,in application,there are always certain deviations between the incident beam lighting on the BSG′s face and the ideal one,such as the lean of incident angle,wavefront distortion,etc.. These deviations affect the accuracy and validity of BSG′s sampling signal. In this paper,a model of BSG′s using state is established based on the theory of Fresnel holographic recording and representation,and the process of beam sampling is further studied. This paper emphatically analyzes the location and energy distribution of sampling spot when light wavelengths have wavelength shift,incident angle deviation or wavefront distortion. The analysis results of this paper provide theoretical reference for practical engineering of BSG in application system.

The layout of 1×N optical power splitters with uniform outputs and low excess loss is presented in this paper. The novel splitter consists of cascaded asymmetric Y-branch waveguides based on total internal reflection. Its optical characteristic is thoroughly simulated and analyzed by using finite-difference beam propagation method (FD-BPM). The simulated results show that the power uniformity of the splitters is less than 0.3 dB at wavelength of 1.55 μm. The proposed structure has the advantages such as simple structure,low-loss,little dependence of wavelength and polarization.

Microstructured polymer optical fiber (MPOF) are rapidly developing as an alternative to conventional polymer optical fiber. They are cheaper and simpler to make,and aslo have a wide varity of new optical properties through tailoring the hole structure imposed on the preform and maintained within the final fiber. However,one important issue that needs resolution to facilitate successful commercialisation is cleaving of the fiber to form an optical ending face for coupling. The impact of the following parameters is considered in cleaving microstructured polymer optical fibers:fiber drawing conditions;temperature of cutting blade,and fiber temperature during cleaving,etc. Optically acceptable MPOF ending faces can be produced by employing a “hot blade/hot fiber” combination.

Focused on the coefficients′ interscale correlations of anti-aliasing contourlet transform (AACT),a hybrid research method which includes conditional probability,mutual information and mutual correlation and the generalized non-Gaussian bivariant distribution are proposed to model AACT coefficients. This model improves the solution method of shape parameter ξ. Experimental results of ξ and m1,1 (moment of order 1) show that the probability of ξ<1 is about 99.5% and the average value of error measurement of m1,1 is about 2.77%,which means this model is a good candidate for joint distribution of AACT coefficients.

The solution method of ultraviolet propagation function involved multiple scattering through grid generation is investigated. Through curring up many spatial grids in space,the radiant intensity in each spatial grid is discreted in a direction Ω using relative weight factor. According to a given emission source specification as well as the boundary condition and the initial condition,it can be resolved with high efficiency and precision through splitting method. The contributions of source-term and propagation term are calculated seperately in each period of time. By Laplace conversion,the analytical solution of partial differential equations are solred separately;the each step′s contributions can be obtained;then the value of next moment can be solved. Compared the results with that using Monte-Carlo calculation method,it saves more time by using grid generation to solve the function of ultraviolet radiation propagation,and its largest computing error is 6.9%.

For the requirement of high efficiency light emitting diode (LED) luminaries and the characteristics of automotive headlamp exit beam,based on non-imaging optical theory,a theory model for new type LED parabolic reflector optimal design is established to maximize the utilization of light energy of the reflection cup and to realize the asymmetric light intensity distribution of the headlamp exit beam. An optical system of new type reflective LED automotive headlamp is designed. By TracePro simulation it shows that the geometry collection rate of reflector reaches up to 96% without considering the loss. In the screen that places at 25 m the width of the field of view is greater than 10 m. The emitting light distribution of low-beam has a distinct cut-off line and the light distribution of high and low beam are both satisfying the national standard,with the structure size of entire lamp only 160 mm×80 mm×25 mm.

Schlieren device is an important method for the measurement of transient flow field. The illumination effect serves as a vital role for its measuring result. A lighting system based on light emitting diode (LED) was designed to solve the problem of schlieren′s illumination. The structure and etendue of schlieren device was analyzed,and the light flux of the object plane was calculated. According to the calculated result,the type of LED was selected,the layout and the optical collimating system were designed. The model of the lighting system was built through Tracepro,the illuminance distribution and light flux were analyzed. The calculated result indicated the lighting system based on LED met the challenge of schlieren device.

A new encryption algorithm of virtual optics is proposed based on computer-generated hologram and double random phase encoding system. The algorithm uses two-way double random phase encoding system which has same random phase masks but different parameters to achieve. In the encryption process,the plaintext is modulated by the first way double random phase encoding system,and its in-line hologram is superposed on a reference beam that generated by another double random phase encoding system,the ciphertext is the outcome of its filtering. The plaintext is recovered by calculations in reverse order of encryption process. Analysis proves that the virtual optics algorithm is valid. Computer simulation shows that the algorithm has a strong ability to resist the attacks of chosen-plaintext and ciphertext-only.

Rapid processing of CCD star image is a key technique for star sensors as well as other optic surveillance sensors. The foreground of CCD star image is different from the background distinctly. A method of star image de-noising based on Top-hat transformation and median filter is presented. This de-noising method is able to hold the edge of stars. Then a new algorithm based on grads Hough transformation for star point rapid locating is presented. The new algorithm is simpler and high efficiency for star image processing. Experiments on real CCD star image with size of 752×580 indicats the validity of the algorithm.

Aiming at the limitations of unimodal biometric identification,a recognition algorithm for multibiometric fusion based on hand vein and iris is proposed. To verify personal individual,the hand vein image and iris image are preprocessed,and then the feature codes of hand veins and iris are extracted from the detail images obtained using wavelet transform. The wavelet features of hand vein and iris are connected as a joint feature vector (JFV) at feature level fusion,and the minimum distance classifier is employed for feature matching in identity verification finally. The performance of the proposed method is tested using the TJU hand vein image database and the CASIA iris database. The result demonstrates that the recognition performance of the proposed method is obviously higher than that of single-biometric recognition algorithm,which provides new scientific thought for the further research on biometrics.

A technique for passive millimeter-wave scanning imaging based on optical upconversion is designed for millimeter-wave photon imaging radiometer system. The millimeter-wave signal is transferred to the sidebands of the optical carrier by an electro-optical (EO) modulator,and filters are used to suppress the optical carrier. The optical signal of the remaining sideband is converted into a photocurrent by photodetector,and then the photocurrent is converted to the voltage signal by transimpedance amplifier. The lock-in amplifier is used to read the output voltage signal. The brightness temperature image of the objects is obtained by signal processing. We analysis the relationship between antenna scanning speed and antenna temperature contrast,system output signal,noise source,signal to noise ratio,and sensitivity etc. The sensitivity of imaging systems is discussed in detail. Several methods are proposed to improve the sensitivity of the imaging system,which provides a theoretical guidance for the realization of the millimeter-wave radiometer real-time imaging system project.

Based on the application background of laser imaging radar,the paper mainly researches the technology of gate viewing imaging laser radar. Firstly,through the discussion of the principle of gated imaging laser radar,the simulation scheme of the imaging system is designed. Secondly,each section of the imaging system has been researched,and then the system related technical indicators can be obtained. Thirdly,according to the actual engineering design,the simulation system is built by LabVIEW,including several modules such as atmosphere module,object module,noise module,laser transmitting module,laser receiving module,data processing module and image display module. Finally,the simulation system is integrated on the basis of each module,and then the simulation results can be acquired including the different range results and different model imaging results. And at the range of 10 km,the imaging range resolution can reach 1.5 m. The actual range gated imaging experiment result proves that the simulation system is practical.

To design high resolution remote camera optical system,this paper researched the issues in the during of the design of reflective optical system,proposed the three-mirror-anastigmat (TMA) optical systems of field bias,full field and annular field according to fields distributing,and finished its optical system design which was characterized by the spectrum band of 500-800 nm,focal length of 6000 mm and F number of 10. The result indicates that the image quality of the optical system approaches or reaches the diffraction limit,which can meet the demand for use of high resolution space cameras. Through analyzing and comparing the difficulty in fabricate and assembling of the three kinds of the three-mirror-anastigmat optical systems,it can be a special reference to the design of other large aperture and long focal length space telescope.

The digital post-processing is needed to restore the image of high quality from the blurring image output directly from optical sparse aperture imaging systems. The common method for post-processing is the Wiener filter,where the important parameter is the point spread function (PSF) which should be known. The Wiener filter will deconvolve the convolution effect if the PSF is the precise impulse response of the optical sparse aperture system. Usually it is hard to measure the PSF experimentally. On the contrary,it is easy to calculate the PSF based on designed array configuration of the optical sparse aperture system. In order to evaluate whether the calculated PSF is adaptable to the image restoration,a theoretical analysis of the image restoration has been done by using these two kinds of PSFs. The results show that the calculated PSF works well in the case that the co-phasing error is small,while the measured PSF is ineffective.

The structure of spiking neural network (SNN) is presented,which is regarded as the third generation of artificial neural networks (ANNs) and established based on the simulation of network model for biological visual cortex. The conductance based on integrate-and-fire spiking neuron model is given,and then the neural network is applied to edge detection of leucocythemia marrow images. The experimental results show that SNN can be applied in leucocythemia marrow image segmentation. The lower the firing threshold is,the more details will be displayed.

Wavelet coefficients prior statistical models of image have been studied widely in the Bayesian-based image processing scopes. In this paper,we derive a precise prior statistical model based on full Bayesian neural network (FBNN). The parameters of the model can be estimated empirically from a sample image set by modern particle samplers (Montel Carlo) methods. The simulated results based on the prior models of single scale and parent-children scale show the model makes it possible to exploit the dependency between the scales. Furthermore,a novel image denoising method based on scale prior particles sampled from the fitted the single scale and parent-children prior models produces the high quality visual effects and peak signal-to-noise ratio (PSNR).

In order to detect the velocity and concentration field of metal power particles in laser cladding,an optical system is built based on a 100-mW diode laser. A combined lens is designed to collimate the beam of laser,after the elliptic spot corrected by a prism into a circular one. At the last laser beam is extended into uniform sheet laser by a cylindrical mirror. Laser physical model after scattering by spherical powder particles is constructed from Mie scattering theory . Laser intensity distribution is plotted by mathematical software when it is irradiated by green and red light . The research result shows that scattering intensity of green light is two times of red's under the same condition and sub-maximum intensity of 532-nm light is appeared around 20°. So 532-nm diode laser is selected as the light source. Pictures are much better when the angle between charge coupled device (CCD) camera and incident direction is 20°.It provides the theory for a cheap and portable powder flow field detecting system.

On the basis of optimized laser parameter,the effect of laser ablation parameters on the silver nanoparticles colloid was analysed. Particles size,morphology and absorption spectroscopy of the obtained nanoparticles colloids are obtained by ultraviolet to visible(UV-vis) spectrophotometer and transmission electron microscopy. The average diameter and distribution of the colloids are analyzed by Image-ProPlus software. The results show that the Ag nanoparticles with best characterization are those produced at the repetition rate of 10 Hz and laser fluence of 4.2 J/cm2 by ablating for 7.5 min in the distilled water with SDS,with the least average diameter (D=11.88 nm),the narrowest distribution of particle size (δ=19.6 nm) and more homogeneous morphologies. That effects of experimental conditions on the silver nanoparticles colloid can be explained by explosion and melt inducing aggregation of colloidal particles by self-absorption of laser pulses.

In order to study the characterizations of different metal nanoparticles colloids produced by laser ablation,under optimized ablation conditions,the Ag,Au and Ti nanoparticles colloids are prepared and analysed. The measurement results of UV-vis and transmission electron microscope (TEM) show that the Au nanoparticles are of the best characterizations. the average diameter is the smallest,the distribution of particle size is the narrowest and the morphologies are homogeneous. The mechanism of the results is not yet clear and is the subject of further investigations.

Based on the theoretical and experimental analysis of infrared-visible up-conversion materials an infrared laser anti-counterfeiting recognition system based on the phase-locked amplifying technology is prepared. The transmitter is composed of constant voltage source,frequency generator and infrared laser diode. An electricity signal with given frequency is modulated on infrared laser diode. The assigned frequency is 800 Hz,and the wavelength of peak value of infrared laser is 975 nm. The receiver part is composed of optilcal filter,photosensitive tube,prepositive filter,phase-sensitive detector,low pass filter and comparator. The receiver can detect the up-conversion visible light. The center wavelength of the filter is 553 nm. The results show that the system is feasible for recognizing of the fifths RMB,new edition Pound,new edition Vietnam currency,some expensive cigarette and wine. Because of the advantages of high reliability,small volume,low price,easy spread,and simply integration,the recognition system would play an important role in the action of cracking down on counterfeiting offenses.

A novel method for fabricating phase diffractive elements is proposed. Distinguished from the common phase holographic interference,we used single laser beam coming out of the direct writing system to inscribe phase-type gratings. The direct writing system can modulate the intensity and polarization of the Gaussian laser beam. Based on the control ling of the exposure time,intensity and polarization of the writing light,a series of phase-type gratings were fabricated. The induced surface deformation was directly determined by scanning near-field optical microscopy (SNOM). Some qualitative analysis was made in the article. Compared with holographic interference method,the method above is more flexible,undemanding for the experimental condition,which may become a new way of fabricating diffractive optical elements with complicated surface profile and controllable diffractive characteristics.

The main application background of this paper is using laser cladding technology to process high-speed wire roller. The production lines in the steel rolling industry are different. The wire rollers at different positions in the produce line have different shape. And the different backings of rollers have different process crafts. So it is necessary to explore the mechanics of laser cladding roller with universality. The paper analysed the laser cladding process in theory,and sought one measuring and tracing method adapted to analyzing and monitoring laser cladding process. Based on the temperature field of CO2 laser cladding investigated through high speed camera,the basic things about how to analyze temperature field by Matlab software are introduced,including input and output of the thermal image,the temperature distribution at the direction and its section in molten pool.

In order to research the effects of laser power,scan velocity and beam diameter on the primary and secondary degree that affect the 38CrMoAlA steel′s laser phase transformation hardening,and optimize the technical parameters,the normal experiment was conducted by three factors and three level L9(33) normal experiment table. The effect of laser power,scan velocity on the surface hardness was predicted on the basis of two dimension bicubic interpolatio. Results show that the primary and secondary sequence affecting surface hardness is scan velocity,laser power and beam diameter,and their optimized level are 30 mm/s,1.6 kW and 3.5 mm respectively. Under the three parameters,the hardened depth of laser phase transformation can reach over 0.5 mm. The hardened layer can be divided into four parts. Almost all of the second layer is martensite and this layer has the highest hardness. The structure coarsening happened to the fouth layer,which is the mixture of martensite and ferrite and has the lowest hardness.

Zn0.9Co0.1O powders are compounded by the solid state reaction and prepared for the high-quality target of depositing films. Zn0.9Co0.1O powders are synthesized at various fritting temperatures in order to investigate the structural and optical properties of the powders. The structural properties of a nubby powder are measured by X-ray diffraction(XRD). The optical properties of the target are tested by Raman scattering and ultraviolet photoluminescence (PL) emission measurements,respectively. The results show that the fritting temperature is an important parameter to influence the sample structure. A series of Co substitute Zn and the sample retains original structure in wurtzite lattice with a temperature of 1200 ℃. At the same time the band gap of ZnO crystal lattice is narrowed from the Raman spectrum.

TiO2 film is an important photo-induced catalyzer and it also presents hyper hydrophilicity properties. However the applications of this material are greatly limited due to its low efficiency under visible light. A promising way to improve its photocatalytic effect is to dope with some nonmetal elements. The visible light absorption and hydrophilicity of N-doped TiO2 film on quartz substrates prepared by R.F magnetron sputtering are obtained,with the working gas of Ar/N2,the samples were post-treated by annealing under different temperatures in nitrogen atmosphere. The structure,doping,surface morphology and optical properties of undoped and N-doped TiO2 films by means of XRD,XPS,SEM and UV-vis spectra were analyzed. The XRD results indicated that TiO2 anatase is formed around 600 ℃ and N atoms are doped in TiO2 crystal lattice as shown in XPS studies. For the UV-vis analysis of N-doped samples,it is found that a dramatic red drift occur in the absorbance spectra compared with that of TiO2 thin films,which means a higher visible light catalysis activity. The water contact angle measurement of the annealed samples under visible light radiation for 30 min showed excellent hydorphilicity with a water contact angle less than 10°.

Recently,investigation on InGaZnO acting as channel layer for thin film transistor attracted much attention,in order to meet the demand of flexiable display devices. Ga2O3,In2O3,ZnO powders were mixed up according to a certain mol ratio,after the course of grinding,presintering,grinding,pressing and sintering,InGaZnO ceramic target was obtained by solid-state reaction in atmospheric pressure,and the target was tested by X-ray diffraction. Moreover,pulsed laser deposition method was applied to grow InGaZnO films at certain temperature,using quartz glass as substrate. The film was carefully examined by atomic force microscopy (AFM),transmittance specturm and Hall-effect,finally got semiconductor thin film with high smoothness,high transmittance in visible region and excellent electrical properties. These tasks will bring with experimental results in fabrication of InGaZnO thin films for further researches.

The optical properties and microstructures of YbF3 thin films by thermal evaporation and argon ion-assisted deposition are studied. The transmittance,refractive index and extinctive coefficient of YbF3 thin films are measured by photometer and ellipsometer,respectively the cross-section and crystalline phase structure are characterized by scanning electron mircoscope (SEM) and X-ray diffraction (XRD) meter. The experimental results show that the structures of YbF3 thin films deposited by the two methods are all amorphous;YbF3 thin films deposited by ion-assisted have a higher packing density,the packing density of YbF3 thin films increases and the peak of water absorption decreases more significantly than that by resistance-heating evaporation,and the adhesion is better. Moreover,the higher-energy argon ion-assisted deposition under 120 V bias voltage can get YbF3 thin films with higher packing density close to 1 and almost completely eliminating the loss of water absorption.

The atomic and electronic structure of anatase TiO2 with impurity of N,C and S are studied by first-principles pseudopotential calculations based on density-functional theory (DFT) in this paper. The results show that the impurity react oxidation and the nearby Ti atoms react reduction. By analyzing band structure,density of states and charge population,it is concluded that an impurity band appears in the gap and Fermi energy goes up. The spectrum generates red shift and the activity of photocatalysis heightens because of the gap decreasing. The response of wavelength reaches the range of visible light.

The mechanism of dislocation formed and strain released in GaN epitaxial layer grown on sapphire substrates by molecular beam epitaxy (MBE) was investigated by comparative analysis of the in-situ spectroscopic ellipsometry (SE) data. It has been found that the dislocation density was related to the extent of strain relaxation in GaN film grown on just sapphire substrate during buffer layer ramping and that threading and spiral dislocation was suppressed effectively by using vicinal sapphire substrates. The results indicate that using vicinal sapphire substrates is a practicable way to suppress spiral dislocation and to improve crystal structure of GaN films.

Key parameters of airborne weapon such as 3D velocity and 3D pose can be acquired by processing images taken by two high speed cameras mounted in the cabin,which is fixed under the fighter plane. In order to improve the precision and reliability of the video-metric system,a new design based on monocular and binocular video-metric is realized separately. Theory and measurement results show that the angular accuracy of this system is prior to 0.1 degree and its displacement accuracy is prior to 0.5 mm,which achieves the testing requirement in airborne weapon bombing/launching period.

Refractometry based on multimode optical fiber with large core is presented. The multimode fiber (MMF) with the cladding/core radius 62.5/50 μm is connected with normal single mode fiber,which composes a single-multi-single (SMS) mode fiber structure. The structure is sensitive to the surrounding refractive index and is used as a refractometry. The demoducation system is made of the broadband amplified spontaneous emission (ASE) source and optical spectral analysis (OSA). A simple theoretical analysis of the refractometry is given and a HF corrosion method is proposed to enhance the performance of the refractometry. Experimental results prove the feasibility of the refractometry.

Machining mass products need a rapid measuring system,but the traditional contact measuring methods do not meet the demands of mass production. Meanwhile,some non-contact measuring methods,for example,structured light methods and photogrammetry-based systems,they usually require intense manual intervention during operating. A 3D coordinate laser non-contact measuring system using 1D laser sensor and a servo control coordinate system was proposed to fast collect dense 3D points of the objects. The laser sensor is installed on the z-axis perpendicular to the xoy scanning platform. The errors are removed by designing filters and calibrating the entire system. The measuring results show that the measuring errors of single point are less than 10 μm and the measuring errors of the whole surface are less than 20 μm.

Specialized mirrors are normally used as prefocusing and postfocusing optical elements in synchrotron radiation (SR) beam lines. These mirrors are used for extreme grazing incidence in the vacuum ultraviolet,X-ray regions. Mirrors are typically segments of far-off axis aspherics off-axis aspheres,such as cylinders,ellipsoids and toroid with radii of curvature from tens of millimeters to infinite. Surface figure or shape error for these mirrors is generally represented by root mean square (RMS) slope errors. Typical tolerances for these mirrors are 3 μrad for RMS slope error and 0.3 nm for RMS micro-roughness. Measuring the mirrors used in SR with high precision is very important. The long trace profiler (LTP) is used for metrology in SR besides optical interferometer. The LTP is used for testing surface slope error of SR optical elements in world and is not adopted in visible optics generally. Optical metrology methods used in SR are introduced in this paper.

With a measurement system for power and nonlinearity calibration,a suit of calibration facility to measure optical fiber power meter has been established in this paper. The nonlinearity coefficient of optical fiber power can be measured with triplet superposition method. The wide spectrum fiber power meter accuracy is largely increased by cryogenic radiometer,silicon trap detector,thermopile detector coop-eration. The optical input interface is solved by a conversion clamp. A special method is adopted in this software to eliminate the optical power drift and the fluctuation of zero power point in order to improve the measurement accuracy. The detailed measurement uncertainties are estimated and a conclusion is also made.

A modal wavefront sensing technique of using binary holography optical element(BHOE),and a detail theoretical analysis on the principle of the modal wavefront sensor of this type are presented. The primary design approach of the BHOE is introduced. The effect on the unknown beam intensity of the aberration of single Zernike mode is also studied. The BHOE is encoded and designed with computer,and simulations are carried out to verify the feasibility and validity of the wavefront sensing approach. With the optical parallel processing ability,the speed of the wavefront sensor is highly improved,eliminating the computational overhead or post-processing in wavefront reconstruction stage. Compared with the conventional wavefront sensors,our technique is suitable for the large bandwidth situation,e.g. the atmosphere transmission in airborne enviroments,the requirements for high update rates,the large scintillation environments and so on.

An on-axis,vibration insensitive,polarization Fizeau interferential system is built. In this arrangement,a multimode semiconductor laser is used as the light source,of which coherence in conjunction with a polarization delay-line is used to effectively separate out the orthogonally polarized test and reference beam components for interference. Spatial phase-shifting system is realized by a 2D grating and a polarizer group. The four ties of rays including two ±1 diffraction rays with the same intensity are projected through four polarizers,of which the axis directions are 0°,45°,90°,135°,and four π/4 phase shifting interferograms are received by one CCD simultaneously. By using the 4-bucket algorithm,wavefront to be tested is recovered. Flatness of a parallel plate surface is measured by this system with PV of 0.068 λ,RMS of 0.013 λ (λ=650 nm) and by Zygo interferometer with PV of 0.063 λ,RMS of 0.012 λ(λ =632.8 nm). The two results obtained are in close agreement.

An image edge is usually complicated in complex background. An ear-edge-extraction method based on wavelet modulus maxima is investigated in this paper in order to solve the contradiction between the requirement of regional precision and the property of anti-noise in the process of edge-detection. Firstly,the images of wavelet modulus maxima at three different scales are obtained after image wavelet decomposition. Secondly,these images are separately transformed to binary edge images which are superposed then. Thirdly,noisy points outside the skin color region are excluded by using the binary image of skin color and then the edge image is obtained. After morphological processing on the original image,the binary image of skin color can be obtained with prior knowledge of side face. In this method,the technology of image superposition based on wavelet modulus maxima of multi-scale is exploited to solve the problem that the ear features of internal and external edges are hard to be extracted. Experimental results show that this method is effective in complex background.

A new auto-focusing function for microscope measurement is presented after the research of imaging and focusing principles in order to,in automatic microscope measurement techniques,not only enhance the accuracy of the focus value but also suppress noise. At first,the measuring edges are detected by the improved SUSAN algorithm and lens is moved. When the total of edge points detected is least,then the best-focused lens position is found. We tests in the same condition for 30 times,and experimental results indicate that standard deviation of focusing position in coarse focusing and in fine focusing is 0.000 and 0.0011 respectively,focusing in Gauss noise case is 0.0126,and focusing in salt-and-pepper noise case is 0.0033. BW is accurate in focusing degree,unimodal,sensitive to focusing position and insensitive to noise compared with traditional focusing functions. BW is one of the superexcellent focusing evaluation functions with simple principles,which is a computationally efficient alternative for microstructure measurement.

A wave-front reconstruction technique of cyclic radial shearing interferometry (CRSI) based on least-squares is proposed. First,it divides a single CRSI figure into four sub-figures and then obtains the phase difference distribution of the interferogram by least-squares iteration. By using the wave-front reconstruction algorithm of CRSI,the real wave-front can be obtained with the phase difference distribution. The simulations show that the accuracy is better than λ/50 (peak value,PV) and λ/300 (root mean square,RMS). The feasibility of this technique is experimentally verified. This technique overcomes the problems of spectrum shifting and low precision,which exist in traditional wave-front reconstruction of CRSI based on fast Fourier transformation(FFT). And it can be used to reconstruct wave-front with only one CRSI figure,and also can be used in dynamic measurement of beam wave-front.

The relationship of distribution coefficients of decay linewidth and exponential terms is linear in the autocorrelation function of dynamic light scattering signal. When the linear estimation and nonlinear least squares method are combined,double exponential algorithm is improved. By improving algorithm the initialization parameters are reduced and four parameters optimization problem are changed into two parameters optimization problem so that fitness results is more stability,higher accuracy. Therefore the inverted results of particle size are more accurate. The autocorrelation function of light scattering signal of 100 nm and 1000 nm with two-peak distribution particles is inverted. Inverted error of improving algorithm for noise-free autocorrelation function is zero,which is superior to double exponential algorithm of at least 1.708%. For inversion of noise autocorrelation function,improving algorithm reduces the error of 0.558%-5.738%. The results show that the improving algorithm is better than double exponential algorithm in the capability of optimization and tolerance of noises.

Simultaneous phase-shifting technology is used to capture several interferograms with certain phase intervals in different spacial positions at the same time. It can be applied to dynamic measurement because of its simultaneous interferograms-capturing characteristic. In order to guarantee the precision of the spacial phase-shifting,a method for calibrating the phase-shifting values of the polarizer array is proposed to fulfill the need. Based on the simultaneous phase-shifting interferometer,two methods by use of PZT and Soleil-Babinet compensator are utilized to obtain the phase differences of the neighbouring interferograms and the transmission direction differences of the corresponding polarizers. The experimental results indicate the average transmission direction error of the phase-shifting polarizer array is less than 1°,which can guarantee phase-shifting precision in the simultaneous phase-shifting interferometry.

In order to improve the measurement precision for intersection measuring system with double-charge coupled device (CCD),a mathematical model for measuring system is established according to geometrical imaging principle. Through analyzing the measure accuracy of the measuring point in the system,the effect of the visual sensor structural parameters such as the angles formed by optical axes of two cameras across a baseline,baseline length on the measurement result is investigated. The simulation results indicate that with a symmetrically-set and longer focal length doube-CCD measuring system,when the angles formed by the optical axes across a baseline are between 30° and 70° and the measuring point is located in the center of the system,the higher coordinate measuring accuracy can be obtained. The results is evaluated in designing double-CCD visual sensors.

The nano-displacement measurement based on the principle of optical lever is a contactlessly measurement technology,which has been extensively used in industry and scientific research fields. In this study,with the aim to solve some intractable issues in existing optical lever apparatus,such as low resolving power,low precision,and discommodious reading device,we present a multi-amplify and data auto-collecting system with real time technology based on optical lever and position sensitive detector (PSD) sensor,and design an apparatus to measure the linear expanding coefficient. According to the multi-amplify technology,the tiny displacement is amplified significantly,meanwhile,artificial error is eliminated based PSD sensor and LabVIEW data collecting and analysis platform. The experimental measurements indicate that the system repeat precision of brassiness,iron,aluminum and red copper is 7.5,7.2,7.6 and 8.1 nm.

By using trial observations data from Hulu island in Bohai,Pingtan island ,Dongshan island in East China Sea,Woody island in South China Sea during 2002-2008,physical parameters (characteristic refractive heights,refractive structure parameter values) as well as some relevant electro-optical system propagation parameters based on Bulk flux algorithm and ray tracing program are studied statistical in this paper. The accumulative probability of the positive characteristic refractive height in Dongshan island is above 90%,the percent of high refractive-index soructure parameter (C2n) values (C2n>10-14) is about 50%,which is higher than that in the Pingtan island and Woody island obviously. The cumulative probability of the optical horizon reduction greater than 4 km is close to 50% because of the subrefraction. Dongshan island and Hulu island are under the strong turbulence,the probability of the coherent length smaller than 15 cm is 60%,40% respectively. Its statistical result and the analysis method may provide the information for the marine electro-optical system test environment safeguard.

Nitrogen is one of the necessary nutrient elements for crop growth and products,and the monitoring of crop nitrogen nutrition by the real-time,rapid,non-destructive and accurate way is of significance in estimating crop growth parameters,enhancing nitrogen use efficiency,reducing farmland contamination from excessive use of fertilizer nitrogen. The mechanisms of non-destructive monitoring of crop nitrogen nutrition are investigated by spectroscopy and eco-physiological bases. The theoretical basis and method the obtaining the crop nitrogen-specific spectra information are shown,and the portable nitrogen non-destructive monitoring spectrum instrument for crop is designed and manufactured. Based on the data from rice in field,the instrument is tested and evaluated. The results show that the instrument worked stably and finely,which is very suitable to the nitrogen non-destructive monitoring for crop in field.

The disturbance experiment of 3CCD detector is represented in this paper. In the experiment,the 3CCD are irradiated by 488 nm,532 nm,671 nm continuons wave (CW) laser and the single-point saturation threshold is measured. The results show that three pieces CCD of 3CCD response to the laser which is out of its responsible waveband. The laser can make them saturation. It offers beneficial experiences to the further researches.

Optical coherence tomography (OCT) scattering model and Kubelka-Munk (K-M) theory are combined to analyze the changes of optical parameter quantitively in different aging skin in this paper. In the concrete,the Kun-ming mice with 4 weeks,20 weeks and 40 weeks respective are taken as animal model which imaged by OCT system,the scattering property in mouse skin is responded by OCT backscattering signal in vivo. And the changes of scattering coefficient are gotten by OCT scattering model,and then K-M theory equipment is used to obtain the reduced scattering coefficient in vitro. The outcome indicates that the trends of scattering coefficient obtained from OCT scattering model and the reduced scattering coefficient gotten from the K-M theory in aging mouse skin are uniform,which increases with ages. This result demonstrates that OCT can become a potential tool for detecting the aging skin in clinic in the future,which provides the theoretical basis for studying aging skin and skin cosmetology.

This paper describes the distance measurement of optical surface based on optical coherence tomography (OCT). A single-mode fiber-designed OCT system is developed which consists of a near infrared light source,a Michelson′s interferometer and optical heterodyne detection. Distance testing experiment of range cover glasses is carried out by using this OCT system. The result shows this measurement system has the features of high speed(500 Hz),high sensitivity(6.7 μm),high precision(about 2.07 μm),and it is a non-contact type. The designed fiber system is compact and flexible,and it has great potential in optical material testing,optical manufacture,and optical alignment.

In order to improve the measurement accuracy of null ellipsometry,a null ellipsometry based on photoelastic modulation is presented. Azimuth modulation is achieved through a photoelastic modulator and two quarter-wave plate. The ellipsometric parameters are obtained by azimuth measurement of the polarizer and analyzer,for which the first harmonics of modulator frequency cross the zero. Comparing with traditional null ellipsometry,it can eliminate the effect of background noise and environmental disturbance. The measurement principle is analyzed by using Jones matrix. With measured thickness and optical parameters of ZnS film,the feasibility of the null ellipsometry based on photoelastic modulation is thus demonstrated.

A novel demodulation technique for magnetic field fiber Bragg gratings (FBG) sensors based on the monitoring of the polarization dependent loss (PDL) in transmission is presented. Theoretical simulations are realized using the coupled mode theory. It is shown that in certain range the PDL peak value increases with applied magnetic field monotonously. The effects of grating parameters on measurement range and sensitivity are analyzed. The experimental measurements are conducted on FBG inscribed by means of the phase mask technique. A good agreement between experimental and simulated evolutions is demonstrated. Owing to the polarization properties it is possible to obtain temperature and axial strain-insensitive measurements which is demonstrated by theoretical study and experimental measurements.

A novel method for measuring four-degree-of-freedom geometric errors of a linear stage is put forward. A telescope is used to magnify the straightness errors and angular errors in many times. Position sensitive detector (PSD) is used to sense the errors very fast. So the horizontal and vertical straightness errors as well as yaw and pitch errors can be measured simultaneously with high precision. The four-degree-of-freedom measuring system has been developed,and the theory of measurement has been analyzed. The calibration,stability and repeatability experiments are completed. Experimental results and theoretical analyses show that the system has the resolution of less than 0.2 μm for straightness error measurement and 0.3″ for angular error measurement,and the measurement accuracies of straightness error and angular errors are about ±0.7 μm/cm and ±0.3″/cm respectively within the measurement range of 10 cm.

The optical detection method which reflects the changes in the tumor cells growth process by researching on their spectra is obtained. According to the Beer-Lambert law,the changes of concentration of molecules such as aromatic amino acid and porphyrin in HeLa cells during the growth process of cell cycle will result in absorption spectra differences. Measuring the ultraviolet and visible absorption spectrum of the tumor cells can obtain the changes of spectrum during the different cell cycle growth phases. The relationship between cell cycle of tumor cells and characteristic peak of spectral curve can be acquired from the ultraviolet and visible absorption spectrum. The changes of intracellular specified molecules during the cell cycle of tumor cells can be detected by UV-visible spectral method. It provides new ideas for cell cycle studies.

In order to realize non-contact and rapid measurement of surface roughness,a new surface roughness measurement method based on laser speckle and radial basis function neural network is proposed. The validity of the measurement method is verified by experiment,and several main influencing factors are analyzed. By utilizing image processing technique,four feature vectors are extracted from gathered speckle images. The four feature vectors that are nearly correlative to surface roughness include contrast,dark region ratio,gray distribution and binary feature. As neural network has characteristics such as automatically organizing,automatically studying and memory capability etc,these four above feature vectors are taken as inputs of the radial basis function neural network to realize the surface roughness measurement. A number of samples are used to train the neural network,and the trained neural network measured 4 flat-grinding specimens with different roughness values. The results indicate that the measurement method can measure surface roughness in a classifying way. The method can measure surface roughness not-contact and rapidly in high-precision. And the analysis of influencing factors is helpful to in-depth research.

A method based on 4-channel Boltzmann plots technology to measure the electronic temperature of transient plasma is obtained. The results through a serial of experiments by using this theory as well as high-speed photodetector indicate that this method is valid and accurate for the measurement of the transient electronic temperature of transient plasma.

Alignment for radial Hartmann test system (RHTS) and optical testing system is analyzed. A new method of alignment based on the law of refection,is proposed. A laser is installed on a rotary arm of RHTS emitting beamlet to the measured optical system,while a CCD camera is used to record the tracing for reflected spots. In this way,the offset between optic axis and slewing axis can be figured out. The experimental results show that the proposed method is simple and efficient. This algorithm can also be used in the alignment of large telescope.

The research on laser scattering characteristics of an object has guiding significance for object detection of lidar. Automated measurement system of laser scattering intensity can be used to build scale model for laser radar cross section (LRCS) and can also be applied to verify theory estimation. The features that SR850 lock-in amplifier (LIA) have,such as high dynamic reserve,lower drift,low distortion,0.001° phase resolution,meet the demand of week signal detection. The transmission of command and data between PC and SR850 LIA is realized to make the system automate. LRCS of typical samples are measured,the method of data processing and the analysis of system performance are also given. The experiment result indicates that the accuracy and dynamic range of the system is improved by the application of SR850 LIA.

Measuring the thin film thickness by modern interferometry has advantages of the whole test,high precision and non-contact measurement,the kernel of which is to obtain necessary surface shape and parameter by processing interferogram with reasonable algorithms. The pre-treatment of the interferogram is the most crucial and a basal part,which includes the edge identification of based on mathematical morphology,regional extension based on the 2-D fast Fourier transform (FFT) and unwrapped and wrapped phase based on the non-weighted least squares algorithm for DCT. At the result,surface distribution can be obtained,which lays the groundwork for getting the thin films thickness correctly. In this paper,the image collection of the SiO2 film and the pretreatment of interferogram is performed. The result indicates that it is basically consistent to the result tested by Zygo interferometer.

The at-wavelength interferometry of projection optics,which has important research significance and practical value in integration of lithography tool,is one of the core enabling techniques for extreme ultraviolet lithography (EUVL) facing 32 nm technology node and beyond. In this paper,recent developments of at-wavelength interferometry of EUVL optics are reviewed. Several key interferometry techniques are presented in details. The important parameters of the key techniques,such as,measurement accuracy,speed and dynamic range etc. are analyzed and compared. The core techniques in developing at-wavelength intereferometry device are analyzed. Finally,a summary is given and some prospects for at-wavelength interferometry of EUVL optics are proposed.

Fiber-optic connector is one of the most important optical passive devices in the integral fiber-optic communication systems. Its insertion and return losses have great impact on its performance. In order to ensure the performance of fiber-optic connectors and interchangeability,it is necassary to test its end face geometric parameters. This paper analyzes the principle and the characteristics of the geometry parameters automatic measurement of the optical fiber connector end face and discusses the factors that affect the measurement accuracy. It also makes appropriate improvements. Simulation results show that the proposed approach has characteristics of measurement accuracy and high speed. Therefore,the results show that the proposed method can be effectively used for the geometry parameters automatic measurement of the optical fiber connector end face.

Banyan network shows promising characteristics in the practical application of optical information systems and optical interconnection networks. The properties and the connection relationships of banyan network are investigated in detail,and its topological schematic diagram is also proposed. By a cascade of the banyan network and the inverse banyan network,a full-permutation non-blocking double banyan network can be constructed. Based on the identical polarization controling technology and the same spatial structure,the node switch and the routing stage are discussed and designed by using phase spatial light modulator (PSLM),polarizing beam-splitter (PBS),and mirror. The module designed here has a number of advantages:less optical components,compact in structure,efficient in performance,bidirectional operation,and insensitive to the polarization of signal beam. The tested parameters for the 2×2 optical switch show that the full-permutation non-blocking double banyan network proposed here should be helpful in the design of large-scale optical interconnection network because of low insertion loss,low crosstalk,and high-performance.

This paper describes a new short-wavelength ultraviolet communication transceiver system,which is steady and practical ,based on digital technology applying to a real engineering. The low-pressure mercury lamp is used as ultraviolet (UV) source in the system,and field programmable gate array (FPGA) as the core controller integrates for state controlling,data exchanging,modulating and coding. The system has excellent advantages in antijamming ability,maintaining and improvement upgrade. At last,the experiment results illustrate the stable transceiver system is suitable for real-time speech communication in short distance. The fact shows that the short-wavelength ultraviolet communication system can get a data rate of 2.4 kbit/s in the range of 200 m.

When the input optical power is comparable with the saturated power of the semiconductor optical amplifier (SOA),SOA has a large nonlinearity,including self phase modulation (SPM) and cross phase modulation (XPM). SPM makes the signal′s spectrum broaden around the central frequency;XPM produces new frequency parts around the probing light. The different dispersions of the link will change the signal peak power differently,leading to the varied effects of SPM and XPM in SOA. Via effectively setting the central frequency and bandwidth of the filters,the different spectrum changes related to SPM and XPM can be detected simultaneously,in order to monitor the link dispersion,whose range may be over ±30 ps/nm. This technique can be used to monitor the residue chromatic dispersion (CD) and polarization mode dispersion (PMD).

Silicon photonics is a novel technique for high scale optical/electronic integration,with which most kind of optical devices can be achieved. Silicon microring-based electro-optic modulator is one of the most important devices for photonic integration. Compared to the amplitude modulation,optical phase shift keying (PSK) is a better choice for the optical power efficiency. The Mach-Zehnder modulator (MZM) is usually used to obtain the phase shift keying modulation,but its bulky size and producing technic make it hard for the LiNbO3 MZM to be used in the optical integrating system. The μm-sized silicon microring modulator holds the capability of mass-produce and optic integration. Here the silicon microring modulator is used to achieve optical phase shift keying. The coupling mode and 1-D finite difference time domain (FDTD) are adopted to analyze its characteristics and optical-fiber communication. The results show that the signal Q-factor of the silicon microring modulator can be larger than 20 dB,which means the error-free communication is reachable.

The “environment-drifting” coused by the enviromental factors will happen to the work point of an interferometric fiber optic sensors. In the phase generation carrier (PGC) digital demodulation process,when the drifting gets through the integral link,it increases with the growth of time;the large enough drifting will lead to register′s overflowing and the reset of the digital demodulation system,and the last part of the signals of the demodulation result will be hiden. Focusing on the integral effects and using the low-frequency characteristic,a method of low-pass filtering (LPF) elimination is put forward,and the relevant solution is given. The experiment result shows that the method settles the integral effects of environment drifting well.

In-fiber filter has been focused on for many years and has broad applications in fiber optics area. The theoretical analysis of a single-multi-single mode (SMS) fiber based filter is presented. A multimode-measurement is realized based on an interference method in order to prove the excited multimode in the multimode fiber of SMS structure and to provide more accurate parameters used in the theoretical analysis. Designed filters are given to show the validity of the theoretical analysis. Other factors influencing the performance of the SMS based filter are discussed at last.

In order to develop a methane sensor with low-cost and excellent sensitive characteristics,a fiber-core mismatched type methane sensor based on Cryptophane E was designed. The sensitivity of the fiber-core mismatched methane sensor with different lengths of Cryptophane E coating to various concentration mixed methane gas was measured. Optical power versus injection angle for the methane sensor with the best sensitive coating length in pure nitrogen and 12% mixed methane gas were measured respectively. In order to find out the best injection angle,the difference of optical power in pure nitrogen and 12% mixed methane gas were calculated as well. Results showed that the best sensitive coating length is 3 mm,and the maximum optical power difference emerges when the injection angle is at θ=1°. The lowest detection limit of the fiber-core mismatched methane sensor is 2.3%. The optical power increases with the increasing of methane gas concentration.

A hybrid fiber physical and chemical sensing system is developed in this paper,using Fabry-Perot (F-P) type tunable optical filter (TOF) and erbium-doped fiber amplifier (EDFA). The system has two configurations of open loop and closed loop,which can be switched by two 1×2 optical switches. And the system can be used to realize physical and chemical sensing with quasi-distributed ability and high sensitivity respectively. In the open loop system,the EDFA acts as system light source,while the fiber Bragg grating (FBG) acts as sensor. The spectra of FBGs are collected through wavelength scanning of F-P type TOF,and the physical parameters like strain and temperature can be obtained as the results of wavelength demodulation. In the closed loop system,the ring-cavity fiber laser is constituted of EDFA and F-P type TOF. The gas cell made by C-lens is put into the fiber resonant cavity. And when the wavelength of the laser scans through the gain spectrum,all absorption lines of multi-gas in the cell can be obtained. So different gas sensing can be realized at the same time. The sensitivity of strain sensing is less than 3 με,while the sensitivity of gas sensing is less than 75×10-6 with probability of gas recognition at the same time.

To improve the accuracy of demodulation system of fiber Bragg grating (FBG) sensors,a demodulation method of FBG center wavelength based on a fiber comb filter is proposed. A constant temperature channel of the demodulation system is connected with a fiber comb filter,which offers reference points to calibrate the center wavelength of FBG. The under-bit machine collects and processes the photoelectric signal voltage transformed to rectangular voltage pulse. The computer displays dynamically the FBG wavelength demodulation process and calibrates the Bragg grating center wavelength. The experimental results show that,compared with other wavelength demodulators,it has many advantages,such as flexibility,stabilization,easy maintenance,high-speed,high-precision,and so on. The wavelength demodulation system can be used extensively in large-scale multipoint monitor engineering.