At present,one of the urgent problems need to solve is the motor vehicle causes to urban air pollution. In order to analyse the effect of the motor vehicle contribute to the urban air pollution of Beijing,the particulate mass characteristic over Jianxiang bridge was monitored continually with lidar in August of 2007. The representative data which was monitored during Beijing to rehearse olympics traffic control was discussed. The system structure and technical parameters of Mie lidar were presented and the data-processing method was discussed,the particulate mass concentration was retrieved. The particulate mass concentrations with the traffic volume were compared and black carbon (BC) concentrations which were measured in the similar meteorologic condition during traffic uncontrolled. The results indicated that the particulate mass concentration was falling,and there was a good correlation between the particulate mass concentrations and the traffic volume. All these proved that the program of traffic controlled improved the quality of the city air.

We theoretically and experimentally analyzed the principle of frequency quadruple optical millimeter-wave generation utilizing phase modulator along with an intensity modulator based on optical carrier suppression (OCS) scheme. In the experiment,40 GHz optical millimeter wave (mm-wave) is generated by adjusting the bias of intensity modulator and the phase between the two modulators which are driven by 10 GHz radio frequency signal. 2.5 Gb/s baseband data is modulated on 40 GHz optical mm-wave directly and transmitted to the base station over standard single-mode fiber (SMF-28). The experimental results show that the power penalty of downlink data signals which are transmitted over 20 km SMF-28 is less than 0.8 dBm. The eye diagram of the baseband signal is still clear. This scheme simplifies the radio-over-fiber system and mm-wave signals are stable and reliable.

A novel optical fiber Fabry-Pérot (F-P) refractive-index sensor is reported. A micro-hole is made by etching the tip of a cleaved erbium-doped fiber (EDF). We fabricate a self-enclosed F-P cavity inside an optical fiber by splicing the first fiber to another cleaved fiber. The micro-hole by etching is a flute,a microchannel is made by cleaving and then polishing near the flute,and the light could return which results in F-P interferometer unharmed. The liquid could easily get into the F-P cavity by capillarity. According to the F-P interference principle,the reflection spectra pit wavelength of the sensor is linear with refractive index in the cavity. The experimental results show that the linearity is 0.9996 and the sensitivity is 1068 nm/RIU at the refractive-index range of 1.3333 to 1.3899. The sensor is all-fiber structure,having many advantages such as small size,steady structure,high precision,enduring cautery,etc. It could meet subminiature applications for refractive-index measurement.

Based on a single semiconductor optical amplifier (SOA),simultaneously wavelength conversions (WC) of two input data signals are accomplished. The input signals are return to zero (RZ) code with extinction ratio deterioration,the “0” code with lower optical power (not zero),and its polarization state is orthogonal with “1” code. Using the intensity and polarization correlation characteristic of four-wave mixing on SOA,by carefully setting the polarization relationship between one signal and the other,the two modulation signals information are copied to separately the idler of four-wave mixing (FWM). The experimental results show that the output of two-way signal with wavelengths converted has a good extinction ratio (ER).

A chaotic fiber fence system based on a semiconductor fiber ring laser is proposed,in which the laser outputs are framing polarization chaotic light and a part of the fiber ring is taken as sensing fiber. Wherever the intrusion acts in the sensing fiber,it will disturb the distribution state of the birefringence in the fiber,which influences the initial state of the laser. Output waveform changes immediately because chaos is sensitive to its initial value. By a cross-correlation detection of the waveforms in adjacent two frames,the intrusion can be detected. The position of the ring can be converted to the time of the frame with the framing characteristic of the chaotic waveform. According to the relation between the intrusion position and cross-correlation peak value,the intrusion position is located. This method is real time and with stronger anti-interference capacity and the detection results are immune from external environment fluctuations. The experiment results illustrated that the system has a location error of about 45 m,the relative error of 5%,and a good repetitiveness with a 3 km long sensing fiber.

A kind of vector optical fiber hydrophone based on the composite structure of variable cylinder and diaphragm is designed. Firstly,the theoretical model of the hydrophone′s sensing principle and vector building principle is analyzed,the mathematical expression of hydrophone′s phase-shift sensitivity is obtained and the sensor′s design parameters are discussed. Then the probe head of hydrophone is manufactured according to design parameters. Experiments on the sensor′s sensitivity-frequency curve and the “8” glyph directional diagram are carried out in the first class underwater acoustic measurement station of the national defence. This hydrophone′s sensitivity reaches the value -155 dB re rad/μPa(800 Hz),and the experimental result agrees well with the theoretical value. Some errors are mainly caused by that the theoretical model is not accurate enough,and there is also some resonance in the test equipment and the fixing bracket.

Pointing,acquisition and tracking (PAT) system is the key component in inter-satellite laser coherent communications. A novel method to coherent detection of position errors information is proposed. Based on the system composing,this method adds CCD and computer as position error detector. The position errors as the control signal of PAT subsystem drive the receiver telescope to keep tracking to the target. Theoretical deviation of the relation equation is given,and the analysis of the effect of the wavelength stability on the precision is presented. Finally the simulation results validate the method.

A novel technique of one-shot in-line digital holography based on double wavelength illumination was proposed. Two wavelength beams in color of red,green or blue (RGB) are simultaneously used to illuminate the object and produce the in-line digital hologram (DH). After recording the hologram by a color CCD,two in-line DHs recorded with different wavelengths can be obtained by separating the color image into RGB channels. The angular spectrum theory of diffraction was applied in the analysis of the proposed technique. On weakening the object wave in comparison to the reference wave,the summation of the diffraction object wave and its conjugation can be approximately obtained by logarithmizing the in-line DH. The approximating error lies on the object and reference wave ratio. Then the object image can be reconstructed from the two in-line DHs of different wavelengths by applying the transfer function. The reconstruction method was presented. Computer simulations and simple experiment were given to demonstrate the technique. The peak signal noise ratio (PSNR) of the reconstructed image is about 14.2 dB. Which shows this method could erase the interference of twin diffraction image. Finally,the noise sources of the reconstructed images were simply analyzed. This technique can be used for real time imaging and dynamic measuring based in-line digital holography.

A distributed compression method for interferential multispectral image based on set partitioning in hierarchical trees (SPIHT) is proposed,which combines SPIHT with the framework of distributed source coding (DSC) to exploit the strong correlation within and among frames as well as different scales in the same orientation. And an auxiliary reconstruction method based on side information is presented at the decoder to decrease quantization error. To protect the spectral information efficiently,ROI method based on weighted lifting coefficients is performed to priorly encode the intensive interference area that contains most spectral energy. The auxiliary reconstruction method also takes an obvious advantage on ROI coding. The method not only protects intensive interference area but also reduces the loss of the weak interference area as much as possible. The experimental results show that the proposed algorithm obtains about 0.5 dB gains over DSC in transform domain and its ability to fit the original spectral curves is greatly improved compared with other traditional compression methods.

Iris recognition is an effective method of biometrics recognition. Empirical mode decomposition(EMD),a multi-resolution decomposition technique,is adaptive and appears to be suitable for nonlinear,non-stationary data analysis. We adopt the EMD approach to decompose the iris images and select the intrinsic mode functions with proper frequency range for iris recognition. The experimental results indicate that the recognition rate can achieve 99.44%; meanwhile,the complexity of the algorithm can be reduced because the effect of high frequency noise and illumination can be eliminated during our feature extraction process.

Since the object and the camera don′t remain relatively static during the exposure,the captured image would be degenerated seriously. The restoration of the degenered image is necessary. Due to the arbitrariness of the motion form and direction,it is difficult to restore the blurred image. A new method is proposed to restore the image blurred by motion of any form in two dimension,Theoretical analyses are also given out and a corresponding system for experiments is established. During the integral time of prime CCD,series images are captured by a low resolution white-black high-speed CCD. Based on these images,the displacement is calculated,then the point spread function (PSF) is calculated to restore the blurred image. As the experiments show,this method can get preferable results to restore the image blurred by motion of any form in two dimension.

The nonlocal structure tensor of images is defined by using the nonlocal spatial gradients. The eigenvectors of the nonlocal structure tensor consist in a characteristic space for the image,based on which the nonlocal diffusion tensor is constructed. Utilizing the nonlocal diffusion tensor,the nonlocal anisotropic diffusion model for image denoising is introduced. The model differs from the local anisotropic diffusion model in that,not only neighboring pixels but also pixels far away with similar intensities are concerned. The main advantage of taking those pixels far away but with similar intensities into consideration is that the model protects edges and textures much better than the local model.

A compression algorithm of asymmetric 3D set partitioning in hierarchical trees (AT-3DSPIHT) supporting region of interest (ROI) is proposed for imaging characteristics of large-aperture static imaging spectrometer (LASIS). Firstly,the hyperspectral image sequences are decomposed with asymmetric 3D discrete wavelet transform (3D-DWT). Secondly,different coding precisions are assigned to wavelet coefficients in different regions by the method of ROI to protect the hyperspectral information. Finally,the transformed images are encoded with the adapted 3D set partitioning in hierarchical trees (3DSPIHT) algorithm. The experimental results show that the peak signal-to-noise ratio (PSNR) is more than 40 dB at 8:1 compression rate,and the efficient protection of hyperspectral information is achieved.

To solve the problems of overexposure and tailing which were produced by non-ideal exposure control in the space image,an exposure control algorithm based on illumination change and flexible block segmentation was proposed. First,considering the influence of light radiation attenuation bringing by atmospheric absorption,the relationship between light intensity and exposure time of CCD was derived,and the imaging model of the space image was obtained; Secondly,in order to estimate the exposure condition of the last image,the last image was flexibly segmented,and the gray averages of two adjacent blocks were compared for judging whether the two blocks were combined. If the difference of the gray average is bigger than the threshold,the two blocks are combined,others else they are not. The exposure time can be estimated by the two methods. Experimental results indicate that the SNR of the space images increased with 2.49 dB. This algorithm can effectively inhibit the space image producing tailings and greatly reduce the phenomenon of overexposure.

The point spread function (PSF) is sensitive to the changes of view field in a wavefront coding system with a wide field of view (FOV),which means that it is difficult to restore the image only using the central PSF as usually do. Image degradation model is established by partitioning the FOV into several blocks where inside each block PSF-invariance is assumed and image restoration is just the inverse of the degradation process. A Wiener filter restoration method based on FOV partition is proposed,which restores each block respectively using its corresponding PSF and combines them together by interpolation. The proposed method is based on a more accurate model and has flexibility in choosing filter parameters for different FOV blocks. Test results verify its superiority to the traditional method.

The traditional method of computing rotation invariant moments of image,which needs to convert the image into the polar coordinate system,not only increases the computational load greatly,but also creates large rounding error,and results in error rate increase during image recognition and reconstructed image quality deterioration with image moments. To avoid the disadvantages caused during the process of pixel conversion,this paper took the computation of radical harmonic Fourier moments as example,and proposed a new method of computing moments in rectangular coordinate system immediately. The results of the experiments show that the new method can not only eliminate error caused by coordinate conversion,but also significantly reduce computational load.

In order to ensure the security of digital image effectively,a 3D chaotic encryption scheme for compressed image is proposed. The scheme is realized by encrypting the datum stream achieved from compressing the original image. Firstly,the wavelet-based contourlet coding using an SPIHT-like algorithm is utilized on the plain image,and as a result,the compressed datum stream could be achieved which is then mapped to a 3D bit matrix. Afterward,a chaotic sequence is generated by Lorenz chaotic map,and it is preprocessed to a bit sequence which is used to permute and substitute the elements of the 3D bit matrix achieved above. In the end,the processed 3D matrix is mapped back to datum stream,and the encrypted compressed image could be achieved if decoding and inverse transform are performed on the datum stream. Experimental results show that the bit sequence generated by the chaotic sequence has a good randomicity and the proposed encryption scheme not only has a large key space but also is very sensitive to the security key. Moreover,its sub-key is relative to the plain image which could effectively resist the known-plaintext attack,and since the algorithm is carried out in the compressed domain it could increase the efficiency of storage and transmission.

Stereoscopic images need to be observed accurately in many applications,where image distortions are not allowed in the stereoscopic camera and display systems. The concept of vertically axial magnification of the reproduction stereo image is presented,which may have complementary characteristics to the paraxial magnification of the camera. Therefore,according to the basic requirement that the paraxial magnification of reproduction image should be equal to the axial magnification,the eliminating distortions conditions of camera and display system are derived. A design method and flow program for the stereoscopic camera and display systems is proposed. Design examples are given and the design method is proved correct with checking computations. The design method and flow program are exact and simple. Using the design method,stereo image without distortions can be in a much large depth range for front viewing.

Contaminants on the optical surface is one of the key factors that reduce imaging quality of optical imaging system. The imaging system,which is contaminated by particles with the diameter d=0.3 mm and different distances between particles,is examined firstly. The relevant resolution power is obtained by software HYRes 3.1,which is written by Olympus Corporation. Then FDTD (finite-difference time domain) method is used for calculating the distribution of forward scattering intensity. The results show that the maximum intensity changes a little,but location is away from center of image plane,and light energy concentrates on some point as distance between particles falls. At same time,resolution declines. When distance between particles reaches a fixed value,resolution reduces so badly that it cannot be read out by software,and maximum light intensity,which is situated at edge of image plane,drops rapidly. Therefore,the change of the light-energy distribution brought by scattering of particles can reduce the imaging quality of optical imaging system when contaminants quantity on optical surface is too small to change transmissibility.

We present a coordinate measuring method that has been specially devised to perform measurement of coordinates by projected fringe techniques of projectors in three dimensions. It is composed of two parts:one is a target that moves in three dimensions,and the other is a stationary two-dimensional array of photodetectors. The mini-projector is tied to the target,whose projected fringe is monitored by the photodetectors. Application of a phase-shifting technique allows the phase values of the photodetectors to be precisely measured,which are then fitted to a geometric model of multilateration so as to determine the xyz location of the target by a method of optimization. The measuring principle,iterative method,computer simulation and preliminary results are given. The phase-shifting technique has high accuracy,and strong resistance to noise. Iterative optimization for follow-up provides the basis for the calculation. The experimental results prove that the proposed coordinate measuring method can measure the xyz coordinates of the target with high precision.

X-ray phase contrast imaging is of high sensitivity,with which the internal structure of light elements can be observed. It shows the promising application prospects in many fields such as medicine,biology and material science,etc. Grating imaging successfully used the incoherent source,which brought us into a new epoch of incoherent source phase contrast imaging. A new phase-contrast CT method is developed by introducing the helical scanning into the field of phase-contrast imaging. By analyzing the feature of incoherent source in helical trajectory,a fan-beam helical phase contrast extracting method is presented and by referring to Hilbert′s filtered backprojection reconstruction algorithm,the fan beam helical phase-contrast imaging CT reconstruction algorithm based on grating imaging is proposed. Phase information is reconstructed directly by the refraction projection according to the proposed algorithm computer simulations and performance analysis demonstrate the efficiency of the proposed method.

As a rising nano-scale imaging apparatus,photon sieve has been widely used in nano-lithography,large astronomical telescope,aviation vidicon et.al for its following merit:high resolution,small bulk,low weight and easy replication. To pursue high resolution,the diameter of pinholes of photon sieve should be very small,even less than the wavelength of incidence light,but scalar diffraction theory is no longer valid for this condition. So vector diffraction theory must be used. The diffraction model is built based on vector diffraction theory,then design and optimize the structure of photon sieves. To review the validity of this model,numerical simulation has been done. The results show that the focusing performance of photon sieves designed by the vector diffraction theory is good; In near field,the vector diffraction theory model satisfies the design requirement while the scalar diffraction theory is not valid.

The amplitude and waveform of self-mixing interference signal change periodically with static length of external cavity. The changes of the amplitude and waveform are measured experimentally with variation of static length of external cavity. And,the variation of the amplitude with static length of external cavity is calculated by superposing of self-mixing interference signal of multi-longitudinal mode laser. Then,that variation of the waveform is analyzed by considering the effect of feedback light on reflectivity of laser-cavity and laser medium gain coefficient. Results show that,the variation period of self-mixing interference signal of multi-longitudinal mode laser with static length of external cavity is equal to optical length of laser cavity. While,the width of main maximum region of self-mixing interference signal with variation of static length of external cavity is equal to the coherence length of laser which is less than the optical length of laser cavity. The periodical variation of the amplitude with static length of external cavity comes from self-mixing interference of multi-longitudinal mode laser,and that of the waveform is caused by nonlinear effect produced from feedback light acted on laser cavity and laser medium.

The difficulty of phase unwrapping to recover the phase from noise,holes,fringe breaks,undersampling and other degrading influences is a great challenge. On one hand,least-squares approach may provide a smoothed phase,but it cannot limit the transfer of noise,as well as the smoothing characteristic causing errors. On the other hand,least-squares algorithm may fill the holes with data of approaching original phase. We aimed at improving the filling effect,limiting the transfer of noise,a new phase unwrapping algorithm based on binary mask and least-squares iteration is presented. One simulated result and two experimental examples of phase unwrapping using new method showed its validity,the obtained phase which approached original value very well and was much better than the results from single least-square unwrapping operation.

A maximum likelihood streak detection (MLSD) algorithm is presented for the slow moving target(target velocity in the focal plane array is smaller than 1 pixel per frame)in deep space,it can implement the detection of slow target under the low Signal to Noise Ratio (SNR) condition effectively. The target pulse shape information is included in the signal model,and it is an improved version of the Maximum Value Projection Detection (MVPD) algorithm. The image signal mathematics model is built based on gaussian noise distribution,Its theory detection performance model and the real-time performance are analyzed. Monte Carlo simulation technique is adopted in comparing and analyzing the detection performance of MLSD and MVPD algorithm using simulated sequence images. The result shows that the detection probability of the MLSD reaches to 95 percent when the input SNR is 3.5,and the input SNR required for the MLSD is 2.5 lower than MVPD under the same detection probability. (required an input SNR of 6 for the MVPD). The real-time processing capability of the MLSD can obtain 31.25 Mb/s.

The tilt between CCD and diffusion screen will result in the spot geometry and intensity distortion,which will worsen the measurement result of spot distribution. The reason for distortion is analyzed,and the position relation between distorted grids and ideal grids is established by polynomial model. A grid method of rectifying distortion based on uniting pixels is presented. The distorted image of the self-designed and fabricated “standard grid target board” corresponds the standard grid through distinguishing from the borders of the grids. The corresponding relation can help to recover the spot geometry. It can rectify intensity distortion through the image of uniform light. Experiments prove that the means can not only calibrate the spot geometry but also rectify intensity distortion. The calibrating precision is within 1%. The method is very practical in measuring laser intensity distribution.

After long-term service in rugged environment,polypropylene pipeline easily forms defects such as corrosion on the wall,deposition and crack. The defects greatly reduce the performance of the pipeline and easily cause accidents. The rigorous non-destructive inspection to the polypropylene pipeline must be carried. Infrared thermal wave non-destructive inspection technology was applied to detect three kinds of flaws which were embedded in polypropylene pipeline. Data which was collected by IR camera was processed,the typical time thermograph and the curve of logarithmic temperature-time can be extracted. Via to analyzing the time-variation gray scale of typical time thermograph and the slope coefficient of curve,the type and the information of position of flaws can be obtained. Utilizing the software of image processing,the area of corrosion can be calculated. The results indicated that this technology can make fast,direct-viewing,effective examination for the polypropylene pipeline with 3 kinds of common flaws.

The wavelength lateral distribution of high-power laser diode arrays (LDA) is tested. A V-type wavelength distribution is measured typically in the tested LDA. The measurements are carried under different driving currents,indicating that the thermal induced wavelength distribution is in protuberant shape and is opposite to the V-type. Based on the relation between stress and band-gap energy,it is show that the V-type stress distribution in LDA indicates the stress distribution in the laser chip. A linear stress distribution model is proposed to explain the experimental results. This work demonstrates that the measurement of lateral wavelength distribution can provide a useful method to detect bonding stress.

Based on the geometrical property of the vanish points determined by two perpendicular groups of parallel lines,a self-calibration approach was proposed to calibrate the camera′s intrinsic and extrinsic parameters. Some constraints on the intrinsic parameters were established via the perpendicular property of the vectors,which connect the optical center and the vanish points. These constraints can be solved linearly by using variable substitute. Aiming at determination of the lens distortion coefficient,a nonlinear optimization approach,based on nelder-mead simplex algorithm,was proposed when the center to center distance between adjacent sensor elements is known. The intrinsic parameters obtained by the linear approach can be used as the initial value of the nonlinear optimization algorithm. The extrinsic parameters were obtained by establishing a transitional coordinate system. The approaches proposed in this paper do not need the actual coordinate of the calibration points. Extensive simulations and experimental results with real images show that these proposed approaches are both accurate and robust.

PVA/[Gd(NO3)3+Eu(NO3)3] composite nanofibres were prepared via electrospinning technique. Gd2O3:Eu 3+ luminescent nanofibers were synthesized by calcination of the as-prepared composite nanofibres. XRD patterns showed that the composite nanofibres were amorphous in structure,and Gd2O3:Eu3+ luminescent nanofibers were cubic in structure with space group Ia3. SEM analysis indicated that the average diameter of the composite nanofibres was about 200 nm. Gd2O3:Eu3+ luminescent nanofibers of about 50 nm in diameter were acquired when calcination temperature was 800 ℃. TG-DTA analysis revealed that the water,organic compounds and nitrate salts in the composite nanofibres were decomposed and volatilized totally,and the weight of the sample kept constant when temperature was above 600 ℃. The overall weight loss rate was 71.9%. FTIR analysis manifested that the spectrum of the composite nanofibres was almost the same as that of pure PVA,and Gd2O3:Eu3+ luminescent nanofibers were formed above 600 ℃. Fluorescence spectral analysis indicated that Gd2O3:Eu3+ luminescent nanofibers emitted bright red light of 609 nm in wavelength of Eu3+ ion characteristic emission under the excitation of 251 nm in wavelength of ultraviolet ray. Formation mechanism of Gd2O3:Eu3+ luminescent nanofibers was discussed. The technique can be applied to fabrication of other rare-earths composite oxides luminescent nanofibers.

The use of solar reflective coatings on the building envelope can reduce the energy consumed by the air conditioner and provide a thermally comfortable indoor environment. Performance of the energy saving coating is closely related to its reflectance. The higher reflectance in the solar spectrum,the more energy could be saved. The effects of wavelength,incident angle and thickness of the coatings on reflectance are investigated based on the measurement results. The bidirectional reflectance distribution functions (BRDF) at visible wavelength 635 nm and near-infrared wavelength 980 nm are measured and the effects of coating thickness on the normal-hemispherical reflectance which is calculated from the measured BRDFs are discussed. The results show that there is a remarkable peak at the specular direction in the BRDFs. The peak value becomes high as the incident angle and wavelength increase. The thickness has insignificant influence on the normal-hemispherical reflectance,which is 83% at 635 nm and 75% at 980 nm,respectively.

The accuracy and precision of objective refraction from wave-front aberrations are important in the clinical medicine about optometry and ophthalmology. Based on the wave-front aberration data from human eyes,the curvature distributions of wave-front aberration surface are computed,and the spherical and cylindrical objective refractions in pupil plane are obtained. The refractions in the plane located at spectacle lenses are calculated through ocular wave-front propagation. This method takes into account the influence of higher-order aberration on objective refractions of human eyes. By analyzing the difference between the objective refraction from wave-front aberration and the subjective refraction,the result reveals that the objective refraction with a 4 mm pupil is nearly to the subjective refraction. The mean sphere difference is 0.06D,the mean cylinder difference is -0.07D,and the mean cylinder axis difference is 0.62°. The results show that the objective refractions from wave-front aberration with a 4 mm pupil can be used to predict the subjective refraction actually.

A hybrid "optical tweezers-micro Raman spectroscopy" technique is introduced in this letter. Applying this system,the micro-Raman spectrums of rat erythrocyte and saccharomyces cerevisiae in vivo were obtained. The results show that this technique can obviously improve signal-to-noise ratio compared with conventional approaches. Besides,the damage from lasers on the cells were analyzed. It was revealed that the damage of cell from intense IR laser were much lower than that from the weak Ar+ laser. Finally,the system was also applied in carbon nano-tube (CNT) analysis and Raman spectra from CNT were obtained.

Complicated optical vortices can be generated by holography and their topological structures could be controlled easily,but the obtained diffraction efficiencies are usually low. It was investigated that optical vortex was stored and reconstructed in LiNbO3:Fe crystal by volume holography. The results exhibit that diffraction efficiency of vortex beam was achieved at 26.7% in a crystal just with a thickness of 0.6 mm,and the quality of reconstructed vortex was almost identical to that of original one. Furthermore,by employing Kogelnik′s coupled-wave theory,the results of numerical computations according to the experimental parameters show that diffraction efficiency of vortex beam could attain to 100% as the thickness of crystal reached 1.23 mm with the same crystal and the same exposure parameters.

The sub-wavelength grating was designed,which adapting the harsh requirement of harmonic waves separating in inertial confinement fusion (ICF) drivers. Using the commercial software Gsolver which was developed on the basis of vector diffraction theory,the parameters of sub-wavelength grating which would influence separate harmonic waves,were analysed. The design method of sub-wavelength grating for separating harmonic waves was studied. These results offer the supports for the sub-wavelength grating design.

Impact angle influences the characteristic of impinging jet and material removal distribution in fluid jet polishing,it is important for precise optics polishing to research the material removal model influence. Simulations are done by Computational Fluid Dynamics for fluid jet polishing with different impact angles,and experiments are carried out. The results of experiments and simulations show that the material is removed by particles impinging wear and wall movement erosion,and the influence of impact angle in material removal distribution is induced by the jet thickness,velocity and pressure distribution on work piece wall. Based on impinging jet theory,the mathematical expression of material removal distribution and impinging angle remoual model are educed. Comparing the impinging angle material removal model and the experiment removal profile,it is found that the impinging angle removal model is exact.

With aging treated zinc powder as raw materials,the tetrapod-like ZnO material was prepared by high-temperature vapour phase oxidation method. The ZnO field emission cathode arrays were prepared by the application of thick-film,lithography and screen printing technologies. The cathode plate and anode plate were made of a 5 inch (12.7 cm) monochrome parallel-gate structure field emission display (FED) panel and its field emission performance was tested. The parameters such as the gate voltage,anode voltage as well as cathode thickness which affect the emission performance were analyzed and discussed. The FED can achieve full-screen light emission by driving at about 4000 V anode voltage and 300 V gate voltage. The experimental results show that the structure of ZnO parallel-gate structure FED has a good regulation,a good field emission performance and good application prospects.

Because of the coherent superposition of the diffraction light,wave-front on different region of the mask pattern has different impact on field point in the resist. In order to analyse the contribution of these regions,a theoretical model based on wave-front division was presented. The mask pattern was divided into sub-regions and the impact of their wave-fronts on the diffraction field was investigated. For interference cancellation of the diffraction light,a special region can be finally attained,in which the wave-front has the most contribution to the field point. Study results show that,for the internal point of the pattern,the size of the region is a half-wave zone around the field point; and for points near the edge,the region is generally in a size larger than a half-wave zone,and its scope depending on the shape of the pattern. It is of great significance to improve the simulation efficiency of resist shape error caused by diffraction in lithography. Experiments have verified the calculation results.

A novel Spice model of silicon-based micro-ring resonator is introduced,which can serve as a basic component of integrated optical path. Some basic applications of series-coulped structure,such as double-ring and muliple-ring filter,are analyzed. In addition,the tradeoff between optical gain and 3 dB bandwidth characteristics are investigated. Results show that the larger number of rings,more precipitous resonant peak will produce the better device filtering characteristic.

A high quality tapered monocapillary (TP) using a high-precision fiber optic tower is designed,and the beam size,the transmission efficiency and the gain factor of the TP are measured. The experimental results showed that the beam size of the tapered capillary is below 20 microns. At 8.04 keV,the transmission efficiency of the TP is 13.86%,and at 2.5 mm to the exit of the TP,the gain factor of the TP is 85. At the same time,shadow software developed for beam tracing is used to simulate the beam size,the transmission efficiency and the gain factor of the TP,the simulation results matched well with the experimental results. The beam size of X-ray beam focused by using the TP was smaller than that of X-ray beam focused by using an X-ray lens.

The propagating characteristics of all-dielectric dual-cavity Fabry-Pérot (F-P) structure are studied by the method of transfer matrix,and the general expression of transmittance is also deduced. There are found twelve patterns of combining dual-cavity Fabry-Pérot structure which can produce resonant modes in the band gap,with requirement that the number of dielectric layers between two cavities must be less than the total number of dielectric layers outside the cavities. The first-layer media contacting with F-P cavity must be heterogeneous material when the optical thickness of F-P cavity is odd multiple of quarter-wavelength,otherwise they must be homogeneous ones when the optical thickness is even multiple. When two cavities are fixed in length,the position of resonant modes depends on the number of dielectric layers between two cavities,while the line width (FWHM) relies on the number of dielectric layers outside cavities. When the dual-cavity Fabry-Pérot structure is exactly symmetrical,the transmittance of both resonant modes equals 1.

Optical interconnects for short-distance transmission are becoming more and more important along with the increasing demand on large-scale computing tasks. An analytic method to evaluate the computing performance of optical and electrical chip-to-chip interconnect systems from the parallel computing performance view is proposed. The mesh architecture model and hypercube architecture model are both investigated. The speedup and efficiency are selected to represent the parallel computing performance of an interconnect system. The relation between speedup and computing number,together with the relation between efficiency and computing number,are summarized and analyzed. The comparison shows that the parallel system based on optical chip-to-chip interconnects system has much higher speedup and efficiency than that based on electrical system.

Based on the equation of the movement of the photoelectrons in the parabola coordinates,the trajectory and movement characteristic of the photoelectrons are analyzed for the various cases. The radiuses of the photoelectrons projecting onto the detector are investigated for the photoelectrons taking various kinetic energies. The results show that the fast photoelectron imaging pattern shows the energy feature of the photoelectrons,as well as the information of the space distribution of the photoelectron orbital. The slowing photoelectron imaging pattern is correlative with the energy of the photoelectron,and the photoelectrons focus mostly on the center of the photoelectron imaging pattern.

The principle and realization of the generation of cylindrical vector beams (CVB),including radially polarized beams (RPB) and azimuthally polarized beams (APB),are presented by use of high-birefringence c-cut YVO4 crystal. The device for the production and qualitative measurement of RPB and APB is set up. The experimental results show that when the irradiation is circularly polarized beam,the output beams are cylindrical vector beams with centrosymmetrical polarization and homogeneous intensity distribution,and when the irradiation is linearly polarized beam,the polarization state of the output beam is centrosymmetrical while the intensity is of cosine distribution along the circumferential direction. The cylindrical vector beams have an broad application in many domains,such as optical manipulation,material processing and high-resolution measurement.

Finite-difference time-domain (FDTD) method is used to simulate the light propagation through liquid crystals. The computation window is truncated by the perfectly matched layer absorbing boundary conditions. The incident fields on left connecting boundary and right connecting boundary between total-field region and scattered-field region are calculated independently to introduce plane wave for non-periodic structures. A split-field 1-D auxiliary FDTD method is proposed to calculate incident fields on those boundaries,where the medium are inhomogeneous and anisotropic. Combined these techniques together,plane waves are applicable for non-periodic liquid crystal devices. The simulation results show that the maximum leakage of transmissivity into scattered-field region is less than 3% for twisted nematic cell in on state at 30° incidence. The approach is proved effective for the analysis of optical properties of non-periodic inhomogeneous anisotropic medium.

An experimental system for detecting multi-component toxic gases,which is based on the near-infrared wavelength modulation spectroscopy and harmonic detection technology,is established by taking use of time division multiplexing method. Detecting multi-component toxic gases (CO2,CO,HCN) generated by a fire at one time is completed by this experiment. The full-scales of the three gases are 400×10-6,400×10-6 and 300×10-6. The data carried from the detector is processed simultaneously while the gases are being monitored. The results show that the error between the real gas concentration and the measured gas concentration is less than 0.73% of the full scale. Therefore,this system has a fine linearity and can reach sensitive level for gas detection.

In order to achieve non-destructive variety identification of seabuckthorn juice,a fast discrimination method based on visible-near infrared reflectance (NIR) spectroscopy was put forward. A Field Spec 3 spectroradiometer was used for collecting 40 sample spectral data of three varieties of seabuckthorn juice separately. Average smoothing method and multiplicative scattering correction (MSC) method were used to complete the pretreatment of sample data. Then principal component analysis (PCA) was used to process the spectral data after pretreatment. A total of 120 seabuckthorn juice samples were divided into calibration set and validation set randomly,the calibration set had 90 samples and validation set had 30 samples. Eight principal components (PCs) were selected based on accumulative reliabilities which would be taken as the inputs of the three-layer back-propagation neural network,and seabuckthorn juice varieties were selected as the outputs of back propagation (BP) neural network. Then this model was used to predict 30 samples in the validation set. The result showed that a 100% recognition ratio was achieved with the threshold predictive error ±0.1. It could be concluded that PCA combined with BP neural network was an available method for varieties recognition of seabuckthorn juice based on NIR spectroscopy.

When measure blood glucose concentration using Mid-IR spectral analysis technique,it is inevitable that high-frequency noises and low-frequency baseline drifting will be added to the spectral data. Thus,it is difficult to extract the weak signal of blood glucose from the obtained spectra. An improved preprocessing method based on wavelet analysis is presented,which can eliminate the noise and correct the baseline drifting at the same time. Firstly,spectra were decomposed into detail and approximation at level J which was estimated according to experience. Then the decomposing level J was determined by further analysis of power density Spectra. The noise was eliminated by filtering high-frequency signal at level J with minimum/maxmum threshold and set high-frequency signal at the other levels to 0. And the baseline at level J was fitted with a quadratic polynomial whose coefficients were calculated by least square curve fitting method. Then remove the quadratic polynomial baseline from the spectral data. After applying this preprocessing method to a set of oral glucose tolerance test data,the cross validation result reveals that the correlation coefficient between prediction value and true value is 0.88,and the root mean square error of prediction is 1.14 mmol/L. The precision of calibration is greatly improved.

Visible and near infrared (Vis/NIR) spectroscopy was investigated for the fast and accurate discrimination of rice canopy leaf blast using the combining processing of direct orthogonal signal correction-successive projections algorithm (DOSC-SPA). 120 rice canopy samples were collected with 60 samples for healthy and blast rice canopy leaves,respectively. The calibration set consisted of 80 samples with 40 of healthy and 40 of blast. The remaining 40 samples were used for validation set. Using the new combination of direct orthogonal signal correction-successive projections algorithm,the spectral data of rice canopy was directly orthogonal processed,and then the successive projections algorithm (SPA) was applied for the selection of most important variables,named effective wavelengths (EWs). Finally,a direct linear function was developed between the effective wavelength (775 nm) and rice canopy leaf blast for the discrimination rice canopy leaf blast,which was shown as Y=5.283X. The validation set was used to evaluate and assess the prediction performance of the developed direct linear function,and the discrimination ratio was 95%. An acceptable discrimination result and a parsimonious discrimination model were achieved by this direct linear function. The results indicated that the new combination of direct orthogonal signal correction and successive projections algorithm was a powerful way for the selection of effective wavelengths,and Vis/NIR spectroscopy was successfully applied for the discrimination of the rice canopy leaf blast,and the direct linear function achieved an acceptable discrimination ratio. This study provided a new approach for the further studies such as the on-field monitoring of rice blast,the treatment of spraying rice leaf blast,and the development of instrument for leaf blast monitoring.

Thin-film polarizers were designed by the needle optimization technique. Two single high-index-layer coatings with the difference in layer thickness were used as the starting designs. At 56° incident angle,the spectral bandwidths of the polarizers are determined by the polarization region not less than 20 nm near 1053 nm,where the reflectance of p polarization is less than 2% and the reflectance of s polarization is greater than 99.5%,and the extinction ratio(Tp/Ts)is larger than 200. With the incident angle increasing from 53° to 59°,the spectral characteristics of the two polarizers meet the design requirements although the polarization regions are enlarged and hypsochromically shifted. The tolerances of the thicknesses of the layers uncorrelated are analyzed by the Monte Carlo analysis. To ensure the manufacturing yields higher than 90%,the standard deviations of random thickness for the two designs do not exceed 1.20% and 1.35%,respectively.

Short-wave /long-wave infrared dichroic beam splitters take an important role in two-band infrared imaging optical systems. The choice of substrate and coating materials are discussed. Ge,ZnSe and YbF3 were chosen as film materials and ZnSe as substrate; The coating reflecting the shortwave infrared light while transmiting the longwave infrared (8-12 μm) light is analyzed,and the beam splitter is manufactured by electronic-beam evaporation. The measured reflectivity and transmittance of corresponding band are all above 93%. Such dichroic beam splitters have been successfully applied to the actual optical system.

An on-line thin film stress measuring system based on Hartmann-Shack sensor technique is introduced to measure the film stress of SiO2,TiO2,Ta2O5,Al2O3 and ITO films at different thickness which are prepared by ion assisted deposition,and the effects of substrate materials and preparation parameters on the stresses of SiO2 and TiO2 are investigated in details. The results show that the film stress as a function of the film thickness is linear in the initial stage of coating,and the film stress tends to be a stable value when the film thickness reaches a certain value. The thermal stress which resulted from the different coefficients of thermal between substrates and thin films can be diminished by choosing suitable substrates. In terms of TiO2 films,the thermal stress plays a major role when the substrate temperature is below 150 ℃,but the compressive stress which resulted from the dense structure of films is dominant while the substrate temperature is above 150 ℃. However,the thermal stress in SiO2 films is always dominant at different deposition temperatures. The tensile stress in SiO2 films is mainly caused by the effects of ion assisted sputtering when the chamber pressure is below 1.7×10-2 Pa,and the tensile stress in SiO2 films increases with the vacuum chamber′s pressure increasing when it is above 1.7×10-2 Pa,but the refractive index decreases.

The modulation frequency affects the thermal diffusion depth in sample during the coatings absorption measurement. The absorption value and thermal defects in various depth of the sample can be measured using proper modulation frequency. Theoretical analysis of the impact of modulation frequency on thermal diffusion depth at certain thickness of the coatings is presented. The results show that the thermal diffusion depth is shorter while the thermal conductivity is smaller and the coating is thicker,meanwhile the influence of the substrate is weaker. When the thickness of the coatings does not change,the thermal diffusion depth is shorter while the modulation frequency is higher,and the photothermal signals of different substrates tend to be same.