The closed-form expressions for the mean-squared beam width and the far-field divergence angle of partially coherent Hermite-Gaussian (H-G) array beams propagating in atmospheric turbulence are derived. The far-field divergence angle is chosen as the characteristic parameter of beam directionality,and the directionality of partially coherent H-G array beams propagating in atmospheric turbulence is studied. It is shown that under certain conditions,partially coherent H-G array beams may generate the same directionality as a Gaussian laser beam in free space and also in turbulence. Furthermore,it is found that,the directionality of H-G array beams in terms of the far-field divergence angle is not consistent with that in terms of the normalized far-field average intensity distribution in free space,but both may be consistent in atmospheric turbulence. The result is some different from the behavior of GSM array beams. For the incoherent combination case,GSM array beams with the same far-field divergence angle as a Gaussian beam will have the same normalized far-field intensity distribution as the Gaussian beam in free space.

The method of B3LYP/ 6-31G* in density functional theory (DFT) was used to optimize the geometrical configuration and study the vibrational frequency of GaNm(m=2-7) and Ga2Nm(m=3-6) neutral and ion clusters. The structures and stability magic number regularity of the clusters were obtained,all structures of these clusters are plane. The vibrational frequency of N-N band of nitrogen-rich GaN clusters is 2200 cm-1. There is N2 or N3 unit in the structures of all cluster,and the length of two N-N bonds of N3 of all clusters are equal mainly. The band gap range of nitrogen-rich GaN ion clusters is broader than nitrogen-rich GaN neutral clusters.

The high-order harmonic generation (HHG) power spectra from a one-dimensional model atom irradiated is numerically calculated by linearly polarized 8 fs bichromatic laser pulses composed of a fundamental Ti:sapphire and its second harmonic lasers. It is found that,the distinct double plateau structure appears when the relative phase is zero,and an isolated 110 as pulse can be obtained from the continuous harmonics at the end of the second plateau. This validates Yu Oishi′s experimental research conclusion that continuous harmonic spectra can be obtained at specific relative phase between the fundamental and its second harmonic lasers. The numerical results have been explained by a “three-step” model. Finally,the wavelet time-frequency analysis adopted verifies that the “three-step” model could exactly predict the cut-off frequencies of the bichromatic pulse HHG spectra.

Based on the discrete Fourier transform and Kogelnik′s one-dimensional coupled-wave theory,the characteristics of the laser beam with arbitrary shapes in both temporal and spatial domains diffracted by reflecting volume grating are analyzed. The intensity distributions of the diffractive laser beam in both temporal and spatial domain are formulated. The diffraction performances of the ultra-short pulsed Gaussian laser beam by reflecting volume grating are specifically simulated. The results show that by increasing the grating′s refractive index modulation or selecting the appropriate grating′s period,the angular spectrum and light spectrum of diffractive bandwidth can be broadened;through enlarging the grating′s thickness,its high diffraction efficiency can be achieved. And in this situation,when the central vector of the ultra-short pulsed Gaussian laser beam satisfies the grating′s Bragg condition,the intensity distributions of the diffractive laser beam both in temporal domain and spatial domain are similar to those of the input laser beam,and the diffraction efficiency is greater than 95%. And the results are instructive for the low-pass spatial filtering of ultra-short pulsed Gaussian laser beam diffracted by reflecting volume grating.

To calculate the spectrum of complex structure fiber gratings quickly and effectively is the main basis for analyzing and optimizing the performance of some optical devices,which are composed by superstructure fiber grating,tilted gratings,etc. V-I transter matrix method is proved by the effective index method (EIM) firstly in this paper. The validity of V-I transfer matrix method is analyzed by numerical simulations and experimental results. Compared to the traditional transfer matrix method (TMM),V-I transfer matrix method could greatly improve the efficiency and save the time of calculating N matrixes for analyzing period chirp fiber Bragg gratings (FBG). With the improvement of the precision,the advantage of V-I transfer matrix method will be more apparent.

Sub-wavelength gratings can be applied in the design of various optical devices for the special reflection characteristics. The band structure,eigenmodes and reflection spectra of sub-wavelength dielectric gratings are simulated with finite-difference time-domain (FDTD) method and scattering-matrix method. Simulation results show that the resonant peaks of the reflection spectra originate from the leaky modes and eigen modes excited by external incident waves are different between normal and oblique incident conditions. Further more,the reflection spectra line shape of the grating can be controlled by controlling the frequencies and Q factors of the leaky modes. In the experiments,sub-wavelength gratings in silicon-on-insulator (SOI) substrate are fabricated by electron beam lithography and reactive ion etching methods. Experimental reflection spectra of the fabricated grating agrees well with the simulation results.

Optical en/decoder,based on fiber Bragg grating (FBG) arrays plays as a key role in a 2-demension hybrid time-spreading and wavelength hopping optical code division multiple-access (OCDMA) system. Suppressing the interference between the wavelengths of the encoder is investigated,and the performance of the encoder with the Gaussian apodized FBG is improved. The theory and the model of the encoder/decoder in 2-demension hybrid time-spreading and wavelength hopping OCDMA system are given,and the performance of the FBG encoder/decoder in time domain is analyzed. The mathematic models of the wavelength mismatch in FBG are presented. The auto-correlation peak of the decoding signal is used to quantitatively evaluate the encoder/decoder performance,analyse some kinds of encoder/decoder wavelength mismatch. According to the analysis and simulation,it can be pointed out that large number of son-arrays will improves the system′s capacity for anti-interference,but the biterror rate (BER) performance and data speed will degrade.

A miniature extrinsic Fabry-Perot (F-P) interferometer (EFPI) sensor is fabricated by using simple etching and fusing method. The cavity is formed by wet chemical etching of multi-mode fiber (MMF) in hydrofluoric acid based solutions,then it is fused to the end of a single-mode fiber (SMF) to form a extrinsic F-P structure. Experiment results show that this kind of EFPI sensor has a high sensitivity to strain,but a low sensitivity to temperature. The strain sensitivity is about 0.00095 nm /μ ε. This kind of fiber sensor has many advantages,such as easy fabrication,high-repetition and mass-production,which offers great potential for sensing applications and especially for strain measurements in health monitoring of civil engineering structure.

The flat topping width pulses are obtained by the method of twitter pulse stack. According to the approximately equation of the pulse transmission equation,the transmission characteristic of the stack pulse in linear medium have been analyzed theoretically,and the time profile change rule of the tack pulse are given. It is show that the stack pulse envelope antithetical couplet pulse delay parameter is unstable. If the twitter is greater,the sub-pulse initial pulse width is shorter,and the transmission medium dispersion coefficient is bigger,then the stack pulse time modulation become more serious after the transmission.

A 2×4 90° free-space optical hybrid with polarization splitting is designed and fabricated for intersatellite coherent laser communication. Two phase compensation arrangements by using a λ/4 waveplate are proposed and a phase shift testing method based on the deramping method from a chirped laser is developed. The mathematic analysis,system design and experimental result are given. It is shown that this hybrid works stably,the compensation function works effectively,and the phase test is accurate and simple in configuration.

Optical wireless communications using sub-carrier phase shift keying (PSK) intensity modulation through atmospheric turbulence channel is investigated. Sub-carrier PSK intensity modulation is compared against on/off key (OOK) modulation in the atmospheric turbulence channel. The simulation results show that sub-carrier PSK intensity modulation is superior to OOK in the presence of atmospheric turbulence. On this basis,the low density parity check (LDPC) codes and BP iterative decoding algorithm are applied into the optical wireless communication system,and it is simulated in the atmospheric turbulence channel with combination of sub-carrier PSK intensity modulation. The simulation results show that LDPC codes have excellent error correction capabilities and access to a larger coding gain,and the above scheme can satisfy the need of optical wireless communication system.

In order to reduce complexity of generation of fractional Fourier hologram,according to signal′s fractional Fourier transform and Fresnel diffraction formula,the equivalence relation between them is derived by solving their point spread functions (PSF). So fractional Fourier transform can be transformed into Fresnel diffraction. The object and the hologram plane are sampled by limit of resolution of human eye and size of micromirror of digital micromirror device (DMD). Tiling algorithm is used to generate fractional Fourier hologram,its computation complexity is decreased to O[N2lb(N2/M2)],and a feasible dynamic holographic display is proposed. Finally,the algorithm is verified by DMD holographic display system.

During the numerical reconstruction process of synthetic aperture hologram by use of screen-division method,the center change of the digital reconstruction plane will influence the positions and the phase distributions of the corresponding reconstructed images from the sub-holograms,which will affect the quality of the synthetic numerical reconstruction image. For synthetic aperture digital lensless Fourier transform hologram,a screen-division reconstruction method is proposed based on theoretical analysis. It is pointed out that,in order to get the accurate synthetic numerical reconstruction image,the sub-reconstructed images should multiply with the phase correction factor according to the position of the corresponding sub-holograms on the synthetic aperture hologram plane and then be superposed. Taking the digital lensless Fourier transform hologram with large area acquired by use of linear CCD push-broom technology as example,the screen-division numerical reconstruction experiment is conducted according to the proposed method,and accurate synthetic numerical reconstruction image with high quality is acquired. The experimental result is consistent with the theoretical analysis.

A new approach of digital watermarking based on information optics is proposed. The watermarking image is transformed into virtual object wave after phase retrieval algorithm. Then use the virtual object wave to take the place of traditional Fourier-transformed object wave. It interfered with the reference wave to form Fourier-transformed digital hologram and the contrast is 100% in theory. Hologram is embedded into host image by discrete-cosine-transform and encrypted by security key. It can be extracted with the security key. The watermark is retrieved by reconstruction of optical or digital holography. Theoretical analysis and numerical experiments show that the algorithm has more robustness and practical value to image lossy compression,cropping and filter,comparing with the algorithm based on general digital holography.

Two main determining factors,which limit the quality of the reconstructed image from the microscopic digital hologram by employing the angular spectrum method,are discussed. First are the shape and the size of the spatial filter selected. The corresponding selection principle of the spatial filter is presented,and the experimental result shows that the manual spatial filter exactly selected according to the distribution of the spectrum of the virtual image should be employed to obtain the optimal reconstructed phase image. Second is the phase tilt aberration of the reconstructed image when the specimen is put between two glasses. It is caused by the CCD plane or the sample plane being not perpendicular to the propagation axes. The correction method by the image processing is presented. The theoretical and the experimental result of an onion specimen are shown.

Phase unwrapping is a key step of three-dimensional display in digital holographic microscopy(DHM). On the basis of the framework of Lp-norm,the unified mathematic model of two-dimensional phase unwrapping is studied. A wrapped phase map of DHM is analyzed with several phase unwrapping methods. The results show that the L0-norm algorithm performed best in efficiency,but got wrong result because of too much noise,the L1-norm algorithm could achieve an better resolving,but the most long time consuming,the Lp-norm algorithm used much iterative,but also resulted with aberrations and the efficiency was rather low,the least-squares algorithm and the weighted least-squares algorithm could obtain better optimal resolving and better efficiency. The two algorithms are acceptable in DHM.

The paper established the coupling differential equations using the band-transport model. Using practical experiment's parameters,we numerically calculated and explained the time-dynamic developing process of the holographic storage,and analyzed how the oxidation-reduction degree of the crystal affects the space charge field within the crystal. Only the oxidative crystals can accomplish nonvolatile holographic storage,which its diffraction efficiency after red-light read-out increases with the increase of oxidative degree. Further more we measured the diffraction efficiencies of four specimens with different degree of oxidation-reduction and did comparable experiments of two-wave coupling between reductive crystals and oxidative crystals. The experimental results coincided with the theoretical analysis very well. At the same time,holographic dynamic range M/# and recording sensitivity of oxidative crystal was quantitatively calculated by using experimental curve in which value of M/# equaled to 5.03 (extraordinary light,wavelength,632 nm),but trade off with lower sensitivity.

The hyperspectral remote sensing data contains rich information of reflective spectrum of surface feature,however,the original reflection data includes the massive noises,which affects the absorption feature of reflective spectrum and degrades the data analysis precision greatly. The study of hyperspectral remote sensing data noise filtering algorithm is the key to improve data analysis. The hyperspectral image noise filtering technology is studied. Deep research in high-frequency characteristics of pushbroom hyperspectral imager (PHI) stripe noise,in view of the disadvantages of currently common and several improved moment matching methods,an improved smooth filtering algorithm by row is proposed. The line-average curve of the bands contained strip noise is smoothed and gray value of each pixel in the image is also adjusted to reduce the gray differences between the lines. The peak signal-to-noise-ratio of the gained image has been improved and better effect is got comparing with moment matching method by bands. While strip noise is weakened well,the radiative feature of original image is retained.

Hand vein recognition is a newly arisen biometrics technology,which adopts the net structure of vein vessels to achieve personal individual identification. The hand vein image acquisition system is designed according to vein imaging theory,and consequently construct hand vein image database with high quality. To verify personal indetification,firstly the hand vein image is preprocessed by image filtering and grey normalization,and then the detail images derived from two-level wavelet packet decomposition are used to extract the texture information of hand vein. Finally,the k neighbor classifier and support vector machines are combined for individual recognition. The performance of the proposed method is tested using the hand vein image database constructed by our group under the identification mode. The result shows its correct recognition rate is up to 99.07%,which demonstrates that this system has good recognition performance and possesses wide application prospect.

A robust blind digital watermarking scheme based on non-subsampled contourlet transform (NSCT) and human visual system (HVS) was proposed. In this paper,we establish a model of the human visual system in NSCT domain,using visual masking effect of HVS to adaptive embed watermark sequences. The experimental results show that the digital watermark not only the transparency can be guaranteed,but also has good robustness to noise addition,JPEG compression,cropping,filtering and image twisting etc. Furthermore,the watermark can be detected without original image. This is a perspective blind watermarking scheme.

Scene geometry can be represented by depth images,which need to be transmitted to 3DTV terminals to assist in rendering of virtual view at an arbitrary view-point. Efficient compression is needed to reduce the expenditure for transmitting depth images. Similarity of motion information between video and depth images is analyzed,and a joint video-depth predictive coding scheme is proposed to reuse the motion information obtained in video coding to assist depth coding. The coding scheme comprises two parts,video-depth motion information copy and video-depth motion information prediction. Experimental results show that the proposed coding scheme can utilize the motion information of encoded video efficiently,and improve the coding efficiency of depth images significantly.

The microfacet bidirectional reflectance distribution function (BRDF) model with the two-parameter Cauchy probability distribution,which substitutes for the model with general Gaussian distribution,is used. The directional dependence of emissivity of the object is also taken into account. On the basis,the deduction of mathematical model of long-wave infrared (LWIR) polarization is described. Reasonable simplification and correction for the model is made in order to make the model to be suitable for simulation. Then this paper analyses how to choose the two parameters (σ and q) of the mathematical model and gives the flexibility validation and advantages of the model. The whole process of simulation is done by using C language,the flow of which includes modeling,processing and importing the file into the system of simulation,setting the parameters of polarimetric model,computing the radiation transfer and rendering surface using Gouraud algorithm. The result of polarimetric scene simulation is desirable,which is basically in conformity with real imagers. It proves that the mathematical model and the algorithm in this paper are adequate for the research of LWIR polarization. The conclusion of this paper is significant basis for studying the LWIR polarimetric characteristic of complex objects.

Machine vision is an important method for navigation of agriculture machine. A machine vision algorithm is presented to obtain a guidance directrix for an automatic machine guidance system. Based on the operating environment characteristics of the farmland,this method focuses on a gray-scale transform by using color factor (2G-R-B),and a binary transform by using OTSU threshold method,and a known point improved Hough transform to extract the guidance directrix. This method can solve the problem of low speed of traditional Hough transform. Experiments show that it takes only 100 ms on average to deal with a 640 pixel×480 pixel color image by using the algorithm and correct recognition rate reaches to 92%. It can meet the requirements of real-time processing. It is a fast and effective algorithm for image processing,and is of some practical value.

A new directional operator structure in uniform standard format is presented. From reference to manmade Game,through detection,wash out,competition and tight frame smoothing filtering,a non orthogonal,non perfect reconstruction and non recursive analysis and synthesis filtering macro plan and micro algorithm are proposed. With simplified and optimized strategy of coarsely detecting lines then delicately searching zigzags,and under game rules of minority obey majority and weaker follow stronger,the task of restoring line similar pixels from noisy image is completed successfully. Varity of experiments are made to check the effectiveness,consistency and reliability of proposed algorithm,and some well results are obtained. At final,some faithful objective evaluate on experimental results of new method is made,and the limitation and shortcoming of it is pointed out.

New scale invariants of Tchebichef moments are proposed. Using the falling factor and the first Stirling numbers,Tchebichef polynomials are represented with the linear combinations of power series,therefore,scale factors in moments of scaled image are separated. Then,new power series are transformed back to Tchebichef polynomials. Consequently,scaled invariants of Tchebichef moments can be expressed as linear combinations of original moments. They have lower the computational complexity and no iterative error accumulations. Experiments show that the proposed descriptors have better performance in extracting scale invariant features of a binary image.

The theory of human body infrared radiation indoors plays an important role in the fields of infrared detecting,disease diagnostics,medical treatment,scout and rescuing work after disaster occurring. Presently,the systematic and comprehensive model for detecting infrared radiation of human body indoors has not been studied. To improve the detecting and recognizing abilities of infrared system,a method of calculating the temperature field and the radiant flux intensity of human body is proposed to build the detection model by using infrared physics and heat transfer theory on the basis of bio-heat equation. The temperature field of human body in indoor environment is systematically discussed according to the physical structure and thermoregulation system. The main factors influencing body temperature are analyzed. The experimental results indicated that the main theoretical value is within the error range.

A method for wavefront stitching detection,in which small-aperture Hartmann-Shack wavefront sensor is used to test large-aperture optical system or component,is proposed. The basic principle is to divide large wavefront into certain small ones;then,the slope data in the overlap regions are used in a linear least squares fitting routine to obtain stitching parameters between each sub-frame and the benchmark frame. These parameters are then used to construct the whole gradient map,which is later used to reconstruct the whole wavefront by modal algorithm. The mathematical model of comprehensively optimized stitching mode is established and verified in our experiment. A H-S wavefront sensor with valid aperture 37.5 mm is adopted to test a plane reflector′s 60 mm area and the stitching result is compared with the whole-aperture wavefront that directly acquired by an interferometer. The RMS value of the error wavefront is 0.04 λ and the algorithm accuracy reaches up to λ/40. It proves that the comprehensively optimized stitching mode could be used in large optical surface measurement.

A numerical model for calculating photoacoustic signals from a blood vessel is presented based on the photoacoustic theory. With this model the influences of measurement parameters on photoacoustic signals and the accuracy of measurement of optical absorption coefficient of blood with the fitting-based pulsed photoacoustic method are demonstrated. The computational results indicate that the diameter of the blood vessel has a significant influence on the accuracy of the fitting-based pulsed photoacoustic method and it should be taken into account for improving the accuracy of this method.

Based on the research of space-based spatial object detectors,the optical environment of near-earth space was studied. Modeling of optical characteristics of small spatial object with shapes of plane,sphere,cylinder and cone was carried out,the dependence of the irradiance on objects at a certain distance to the azimuth angles,phase angles of light source and detectors were described. Under the same optical conditions,the brightest object for detector is plane,sphere and cylinder are darker,and cone is the darkest. To verify our modeling,experiments were carried out in dark room to simulate the optical detecting in space. Static and dynamic objects were captured by ICCD camera,by analyzing and processing the images,the correctness of the models and the feasibility of using low-light-imaging system to trace and survey the spatial objects were proved.

The classical NVESD view-field searching for target detection probability couldn′t reflect signal-to-clutter ratio (SCR) influence on detection. The wavelet multi-scale edge detection is adopted to emulate vision system,confining probability of edge (POE) with the root meam square (RMS) of Reynold identical equations which is revised by wavelet multi-resolution analysis,to derive a new algorithm based on wavelet scale. Then the maximum probability was utilized to process a target and its backgrounds detection,so as to derive the maximum probability for target pattern identification. The SCR calculation was introduced into the infrared target detection algorithm to derive the prediction for target detection,classification and identification at high,mediate and low SCR conditions,so that the relation between infrared target detection and SCR is revealed.

The minimum standard model (MSM) structured photodetectors includes photoconductive type and Schottky type. Schottky GaN MSM photodetectors have been made due to its excellent properties of low dark current,high speed,large responsivity,small parasitic capacitance. MSM structured electrodes were fabricated by using conventional ultraviolet (UV) lithography and wet etching,and Au were used as the metal electrodes. The dark current of the fabricated Schottky GaN UV photodetectors was 3.5 nA at 1 V bias voltage. The maximum responsivity of the device was 0.12 A/W at 362 nm under 1 V bias voltage. The rise time of the device was no more than 10 ns,and the fall time was 210 ns. The influencing factor of the response time has been investigated deeply.

The big thermal refractive index coefficient and the thermal expansion coefficient make the thermal effect of liquid laser media greater than those of the solid laser media. Therefore,it is important to study thermal effects of liquid media in gain area during pumping time. According to the energy equation,the wavefront disfortion of the beacon beam induced by the temperature gradient is calculated theoretically in the longitudinal pumping geometry. When the pumping power is increased from 5.9 W to 12.4 W,the Strehl ratio of beacon beam drops from 0.9133 to 0.6174. With the application of wave-front curvature sensing theory,the thermal effect of Rh6G is studied experimentally. Under the same pumping condition with those of theoretical calculation,the Strehl ratio of beacon beam drops from 0.9133 to 0.6174. The beam quality becomes worse seriously.

The p-waveguide thickness which maximizes the power conversion efficiency (PCE) is optimized for quantum well diode lasers. The optimization are based on the simple models of the semiconductor laser′s electrical and optical behaviors,including series resistance,threshold current and internal loss. The structure is designed and the device is fabricated experimentally. For a 1500 μm cavity length and 20% fill factor devices,the threshold current and series resistance are 7.3 A and 4.8 mΩ respectively,and a low internal loss around 0.78 cm－1 is achieved. Under continuous wave operation condition,the maximal electro-optical conversion efficiency of the standard 1 cm laser bar with micro-channel cooler is 63.2%. The corresponding slope efficiency and output power are 1.17 W/A and 36.2 W. The maximal output power is 139.6 W when the current is 161 A. The results prove that the way through optimizing the p-waveguide thickness is an efficient approach to improve.

We obtain a stable tunable single-longitudinal-mode (SLM) TEA CO2 laser oscillation by using a Fox-Smith cavity with a Fabry-Prot etalon inserted in the sub-cavity. A numerical model of the reflectivity of the interference cavity is studied. The influence of the detuned angle and the sub-cavity-matching on the mode-choosing is discussed,and the verification experiment is carried out. Finally we get 140 mJ of SLM output energy at 10.6 μm with repetition frequency of single longitudinal mode as high as 90%,and there is no damage on the elements in the cavity.

Influence of 946 nm dielectric output mirror on single-frequency operation and thermal stability are discussed in detail for the 946 nm laser consisting of thermally bonded Porro prism and corner cube. Degree of linear polarization inside the cavity will not increase significantly by changing the transmittance of p component,while enhancement of the magnetic field applied to the corner cube will not only raise degree of linear polarization inside the cavity efficiently and reduce the output loss,but also decrease the transmittance of p component for the same roundtrip loss difference. Thermal stability and Gaussian beam distribution of this quasi-monolithic non-planar ring cavity are studied by method of propagation matrix.

The calibration of camera with wide field-of-view is a challenging problem because a target of large scale is hard to machine,while using target of small scale cannot satisfy the required accuracy. A camera calibration method based on flexible three-dimensional(3D) target is proposed to solve the calibration problem of camera with wide field-of-view. Flexible 3D target is a target consisting of several planar targets,called sub-targets,which are placed flexibly according to the range of the camera′s view-field. The coordinate frame of the flexible 3D target is constructed based on a sub-target. By using the invariance of the relative positions between sub-targets in the flexible 3D target,the local coordinate frame of each sub-target is transformed into the coordinate frame of the flexible 3D target. By minimizing the re-projection error of feature points on all the sub-targets,the maximum likelihood estimate of the camera parameters can be obtained. Synthetic and experiments show that the accuracy of the proposed calibration method is almost the same as the calibration method using a big planar target whose area is similar to that of the flexible 3D target.

This paper use the method of plane tracking and inclined plane interpolation to weld the container′s corrugated plate,the acquirement of broken line intercept point is the key point. A laser sensor is designed,which can detect broken line intercept point of the corrugated plate. The sensor placed in front of welding torch adopts initiative laser to illuminate the surface of the corrugated plate,the reflection light pass through the limit hole then illuminate linear Charge Coupled Device (CCD),the sensor obtains the distance from spot to CCD by calculating the exposure width. Using least squares to regress plane and inclined plane into two lines and get the intersection by calculating equations of two lines and then to get the accurately broken line intercept point. Surface condition has little influence on photograph sample signal forms by the way model template in order to get boundary between exposure and no exposure. The sensor has high line precision and meets the requirement of seam tracking by experiment. The tolerance of broken line intercept point is in ±0.5 mm ,it provides great helpful evidence to get broken line intercept point when container corrugated plate is welded automatically.

The paper proposes a method to build standard images by simulating the process of optical imaging and CCD sampling,which provides an objective standard for the evaluation of sub-pixel location operators. Also a novel sub-pixel location operator based on gray area interpolation is proposed,experiments prove that the average accuracy of the arithmetic is about 0.11 pixel for linear edge,and 0.24 pixel for circle edge,which is better than the operators based on gradient centroid and gray moment.

Utilizing the method of cross phase,the two-dimensional photorefractive photonic lattice with linear-defect is fabricated in self-defocusing photorefractive crystal by 532 nm laser. The lattice-spacing is 12.8 μm×12.8 μm and linear-defect width is about 32.6 μm. The result proves that it makes localizing and guiding the beam with linear-defect come true in LiNbO3:Fe crystal,which minus refractive index is only 10-5-10-3 because the existence of photonic lattice and the effect of band-gap. The result indicates that it is feasible to fabricate two-dimensional photorefractive photonic lattice with linear-defect in LiNbO3:Fe crystal and localize the beam in the linear-defect. Utilizing this property,it can make optical component which is similar to photonic crystal fibers. It is very important for optical communication′s developing.

The effective magnetic nonlinear response of a 3-dimensional composite created by periodical arrays of wires and split-ring resonators (SRR) embedded into a nonlinear dielectric,was analyzed theoretically,the general expression of the effective permeability for the composite with the consideration of the effects of mutual interactions among the SRR was derived,and the nonlinear magnetic response with and without the mutual interaction effects was calculated. It could be demonstrated that the nonlinear permeability is obviously different for the two cases even though the expressions of the nonlinear permeability of them are very similar. The results are expected to have referential meaning for the realization and design optimization of nonlinear metamaterials.

The mechanism of self-absorption of Ce:YAP crystals which are grown by Czochralski method is investigated in this paper. Samples with different thickness,concentration and annealing condition are prepared and the corresponding transmittance spectra,photoluminescence and X-ray excited luminescence are measured at room temperature. The mechanism of self-absorption of Ce:YAP crystals is studied and the results show that the self-absorption band peaking at 303 nm is caused by charge transfer transition of Ce4+ ions. The study indicates that the problem of self-absorption can been resolved by effectively minimizing the concentration of Ce4+ions.

Through systematic analysis and calculation of the influence factors of the absolute band gap for 2D triangle lattice photonic crystal with air pore,we found the relation between complete band gap and the two main influence factors,fill ratio,background dielectric constant. The results of calculation show that the complete band gap shows up when the fill ratio f>0.4,increasing fill ratio leads to an increase of band gap width,the largest band gap can be obtained where f=0.483. Further,the larger fill ratio is,the higher the central frequency of the gap is. When f=0.483,the complete band gap shows up when the background dielectric constant ε>8. The width of band gap increases with the increase of ε.

A broad-band optical fiber coupler with asymmetric dual-core photonic crystal fiber is proposed based on theoretic analysis. Analysis of numerical simulation shows that coupling ratio of the coupler is flattened in a wider range of wavelength. The influence of the size of air hole between the two the core of the coupler and the polarization of propagating light on the characteristic of coupling by using the finite element method is simulated and analyzed. The results show that the optical fiber coupler with asymmetric dual-core photonic crystal fibers has a 50% coupling ratio with a ±4% dependence on the wavelength over 1.3 μm-1.8 μm,so it is suitable for optical fiber communications and other fields of broad-band couplers with the demand.

In a forward multi-longitudinal mode laser diode(LD)-pumped Raman fiber amplifier,the comb-like waves with more than 100 wavelengths are found on both sides of the amplified signal wavelength. The generation mechanism of the comb-like waves is analyzed and investigated. The four-wave mixing between a number of longitudinal modes of pump LD and the input signal is the fundamental reason that the comb-like waves generate. The effects of the pump power,signal power,signal wavelength and pump configuration on the comb-wave spectra are observed and investigated.

The LiNbO3 nonlinear photonic crystal with two-dimensional octagonal quasilattice was fabricated by applying external electric field. Along the direction of the basic reciprocal vectors,the effective collinear quasi-phase matching (QPM) second-harmonics (SH) of two wavelengths were realized,and along the direction diverging 22.5° from the former direction,so were three other wavelengths. Simultaneously,the non-collinear QPM SH at two symmetric angles with respect to the input wavelength were observed. The collinear and non-collinear QPM harmonics of about twenty wavelengths were obtained in the range of 480 nm,in which the minimum interval of two adjacent fundamental wavelengths was only 3 nm. The same results could also be obtained by rotating the crystal by 45°.

From nonlinear optics and electromagnetic field theory,type Ⅰ and type Ⅱ frequency-doubling phase-matching angle and effective nonlinear coefficient of LBO crystal whose fundamental frequency wavelength is 1064 nm are respectively calculated with numerical method. The range of type Ⅰ phase-matching angle in the first quadrant is about (34°~90°,0~24°),and the square of the effective nonlinear coefficient have a maxmum value when the phase-matching angle approximates (42.2°,56°) and have the second largest value when the phase-matching angle approximates (90°,45.6°). The two values are approximately equivalent. The range of type Ⅱ phase-matching angle in the first quadrant is about(0~90°,45.5°~90°),and the square of the effective nonlinear coefficients have a maximum value when the phase-matching angle approximates (0,90°).

In negative-index materials(NIM) for signal wave and positive-index materials(PIM) for pump wave and idler wave in the structure of PIM/ NIM/PIM,based on three-wave mixing optical parametric amplification,according to the phase matching,there is a maximum noncollinear angle(MNA) when these wavelengths of signal wave and pumping wave are given. The curve of the MNA vs the signal wavelength has been discussed in detail. A analytical expression of spectral bandwidth is obtained through retaining term of first order(when expanding circular frequence of wave vector in Taylor series). Making use of the analytical expression,one has researched this laws of the parametric bandwidth vs the wavelength of signal light,pump light and the noncollinear angle through the method of numerical calculation. Results show that the parametric bandwidth first increased and later diminished with increase of the signal wavelength for the fixed pump wavelength,that is,the maximum parametric bandwidth existed;the parametric bandwidth gradually increased with increase of the noncollinear angle for the fixed pump wavelength and signal wavelength. Besides,the parametric bandwidth also increased with increase of the pump-light intensity. This study provides a basis for investigating optical parametric amplification of negative-index materials.

The conception of nonlinear standing wave (NSW),which is produced by two beams with bi-directions in nonlinear medium,is proposed. The analytical formulas for power distribution,pitch and standing wave ratio of this NSW and phase shift of single-direction beam are deduced. The simulation results show,that when the nonlinearity is weak,the NSW power distribution maintains its cosine type,but there is a pitch modulation effect,which will be shorten when the power increases,and it is proportional to the geometric mean of maximum and minimum indices. When the nonlinearity is stronger,there are two nonlinear effects,including pitch modulation and waveform of NSW modulation effects,the distribution function curve of which is changed from cosine to periodic sharp pulses. The nonlinear phase shift is not proportional to distance,but it changes to periodic monotonic increasing function. The results of this paper are very important to nonlinear medium cavity of laser,frequency selected amplifier,multi-wavelength laser and other nonlinear optical devices.

Driving liquid crystal photorefractive devices with an alternating electric field instead of the dc electric field can overcome some disadvantages induced by the use of the dc electric field,such as the dynamic scattering,permanent grating,and electrolyte. The formation and the application of coherent amplification of gratings recorded in C60-doped nematic liquid crystal under nonbiased sinusoidal alternative electric field were investigated by using two-beam-coupling experiment. Stable asymmetric energy transfer between two writing beams was observed in this kind of cell,indicating the photorefractive nature of the grating recording in nematic sample under the ac electric field. Large beam-coupling ratio was obtained,and the value was compared with that at a dc electric field. Finally the coherent amplification was realized,and the gain coefficient as high as 190 cm-1 was achieved.

An electromagnetically induced left-handedness scheme in atomic vapor medium is proposed. By applying an incoherent pump field to manipulate the populations in each level,the electric part and the magnetic part of the probe field are simultaneously amplified instead of strong absorption. It is shown that both the pumping rate of pump field and the intensity of the coupling field can affect the frequency band of negative refractive index of left-handed material (LHM).

According to high-resolution optical system with long focal length of the structure characteristics and structural constraints of the orbital module in diameter 4 m,the length of the optical system is considered one of the important factors for design. Therefore,a long focal length design of the structure above the optical system is particularly important. By the aberration theory and ZEMAX optical design software,the system to meet the ultra-long focal length and high-resolution requirements and the structure of the length is less than 4 meters. A system with a field of view 1.5 °×0.3 °,the relative diameter of 1/9,the focal length 23333 mm length of the optical system and the length of the structure was 3314 mm was designed. Two ellipsoid ,a pair of hyperboloid and two plane mirror to be the folding mirrors are used in the system. The folding mirror can not only shorten the optical path,but also play a role in focusing.

In the parameter design of lenticular lens used for auto-stereoscopic display system,because the parameters calculated by using ideal optical system are imprecise and the parameters calculated by using optical software are unpractical or complex,a mathematic model based on rays tracing is proposed. The viewing distance,the distance from the display to the lenticular lens and the size of focus spot are taken as the basis for parameter design. The relationship between the radius and the size of focus spot,and the relationship between the thickness and the size of focus spot are analyzed. The parameters of lenticular lens for a 19 inch (48.26 cm) flat display are designed and the viewing zone distribution is simulated by the optical design software called ASAP. Good viewing zone distribution is obtained and its width is 65 mm,which satisfies the requirements for the auto-stereoscopic display having good performances.

A strip-loading waveguide structure was designed with organic-inorganic hybrid material,and its optical field was simulated. A straight waveguide was fabricated and its transmission loss was tested to be 2.0 dB/cm. A Mach-Zehnder interference (MZI) modulator was designed with this structure. By optimization,the distance between the two waveguides in the interaction region was selected to be 30 μm and the length to be 15000 μm. The center electrode width and the gap of coplanar waveguide (CPW) electrode were analyzed to make sure their influence to characteristic impedance,overlap integral factor and half wave voltage. By optimization when the center electrode width was selected to be 9 μm and gap to be 5 μm,the minimum half wave voltage of the modulator is 8.4 V. The device was successfully fabricated and tested. A linear modulating curve was obtained. The half wave voltage in the test was 9.0 V. It agreed with the theoretial value.

The fabrication and characterization of GaN-based 512×1 ultraviolet linear photodetector are reported in this work. AlGaN multilayers are grown in wetel-organic chemical vapor deposition (MOCVD). Material etching,passivation,metal contact and other techniques are used in the manufacture of 256×1 back-illuminated AlGaN detector. The current-voltage (I-V) curve shows that current at zero bias is 4.22×10-12A and resistance is 1.01×1010Ω. A flat band spectral response is achieved in the 305-365 nm. The detector displays an unbiased responsivity of 0.12 A/W at 359 nm. This detector is bonded to a readout circuit with capacitive feedback transimpedance amplifier (CTIA) structure. Two modules are put together to form 512 linear ultraviolet focal plane arrays (FPA). The FPA is measured in 300 K and achieved average voltage responsivity 1.8×108 V/W,the blind rate 9.0% and the response nonuniformities 17.8%. The measurement of signal and noise led to a detectivity of 7×1010cmHz1/2W-1 at 359 nm.

The open circuit voltage changes with the distance between the lens and the solar cells in the concentrating photovoltaic system is studied through the experiment. The voltage peak appears during the distance change. It is confirmed by theoretical analysis that the peak appears due to the open circuit voltage changes with the distance into a Gaussian distribution,and maximum output voltage appears when the light focuss depletion area through fitting the experimental results. In addition,it is studied through the experimental study combined with theoretical analysis that there is logarithmic relationship between the maximum output open-circuit voltage and illumination. It is of great guidance for the current photovoltaic system design and research.

We present a method to prepare a squeezed atom laser via stimulated Raman transition of the Λ-type three-levels atoms in sodium atom Bose-Einstein condensate (BEC) interacting with two light beams,a weaker squeezed coherent probe light and a stronger classical coupling light,and investigate the squeezing properties of this atom laser. The results show that the quantum fluctuation of this atom laser can be periodically squeezed. The squeezing depth of such atom laser is determined by the initial squeezing factor of the probe light,and the squeezing period of that is related to the mean number of atoms in trap,the strength of interaction between squeezed light and BEC atoms,and the detuning of the light.

The influence of the s-wave scattering of background particles on the association or disassociation of molecules in a system composing of two species Fermi atoms with opposite spin and molecules is studied. This influence becomes evidence in the period of evolution when most of the particles in the system are molecules,where the scattering with repulsive potential is propitious to the formation of molecules. Sub-Poisson statistical distribution of the molecule field is observed.

Based on the schrdinger equation,the interaction between the cold atom and Raman laser pulse is investigated,and the density matrix equation is obtained. The cloud location and velocity of atom under the influence of gravity is calculated by using ABCD propagation matrix for atom beam in space. Using density distribution matrix and propagation matrix of atom beam,the relation between the gravity and the population on the energy level of atom is derived. In the end,the influences of the effective Rabi oscillation frequency of Raman beams on the measurement precision of gravity is discussed in detailed.

On-board calibration system is an important technical component for effectively monitoring the performance of radiometric response of remote sensors,the development of hyperspectral technique and information application require more advanced on-board calibration system and more high performance index,which include challenging problems such as nonconforming to spectral distribution of solar,compact system structure and stability. This research promoted a rather full art scheme aiming at above problems,which included tow internal lamps taken as the light source,a minitype integrating sphere used as uniform body,a color temperature correction technique applied for improving the spectral distribution and a standard radiometer fixed interiorly for monitoring the stability of the system. Combining the spaceflight environment request,system design was performed and some experiment results suitable for definite engineering apllication were abtained. The output spectral radiance in visible-SWIR achieves 0.9 times of the radiance of exoatmosphere solar illuminating lambertian surface. The surface ununiformity is within 0.6% and the difference of radiance within ±15°is 1.5%,and the system weight and volume are less than 1.2 kg,0.002 m3 respectively. The bootstrap stabilizing time is 5 min and the radiation output within about 200 h keeps good stability.

The raw spectra of milk powder were detected by means of two Fourier near-infrared spectrometers MPA type and WQF-400N type. Primitive spectra were integrated in different integral intervals to simulate spectra with different resolutions. After being pre-treated with the same methods (Savitzky-Golay smoothing and the first derivative),models for fat content in milk powder were established through partial least square regression (PLS). Comparisons on correlation coefficient R,root mean square error of prediction fRMSEP and mean bias E between the models reveal that MPA type and WQF-400N type spectrometers have the best models at the resolutions of 16 cm-1 and 64 cm-1 respectively. These results show that integral spectrum could compress data and enhance the model′s prediction accuracy,and that an adequate resolution should be selected for special characters of different samples. Both of them ensure the best quantitative analytical result while reducing the work load. It is of no significance to simply pursue higher and higher resolution.

This study explored a new method to choose optimal parameters for support vector machine regression with RBF nucleus (RBF-SVR) and its application on the estimation of moisture content,volatile solid (VS) and the ratio of carbon to nitrogen (C/N) in animal manure compost products using near-infrared reflectance spectroscopy (NIRS). The efficiency of RBF-SVR method was compared with partial least-squares regression (PLSR) mainly using the determination coefficient of prediction (r2) of the standard error of prediction (SEP) and ratio of porformance to standard deviation [RPD (SD/SEP)]. In this study,120 commercial animal manure compost samples were collected from 22 provinces in China. Spectra of the orient samples were scanned with a SPECTRUM ONE NTS from 4000~10000 cm-1,respectively. Results showed stepwise search for optimal parameters was a feasible method for RBF-SVR. The efficiency of RBF-SVR method for moisture content,VS and C/N were all better than PLSR. Robust models using RBF-SVR were developed for moisture content and VS (r2>0.90,RPD>4.0) and for C/N (r2>0.85,RPD>2.5),respectively. Results showed the potential of NIRS with RBF-SVR to evaluate the products quality of animal manure compost,but further research would be needed for the higher precision.