Response characteristic of photodetector, which is caused by polarization state of incident light, is analyzed. The calculation formula of polarization-dependent sensitivity is deduced, and an InGaAs detector is fabricated for the experimental test. In order to test the polarization-dependent sensitivity of photodetector, an experimental system is established, and the polarization-dependent sensitivity of the InGaAs detector is measured. The results indicate that the experimental system has a good stability and the polarization-dependent sensitivity of the InGaAs detector is 0.27 dB under normal incidence，while 0.41 dB under 10° oblique incidence.

Ultraviolet (UV) communication system can provide non-line-of-sight links by exploiting atmospheric scattering of light. The analytic expression of the channel impulse response to received signals is derived and then with this expression the channel characteristic is studied. The relationships between channel lengths, inter symbol interference, bit error rate, bit rate and system geometry configuration are achieved. The results indicate that the channel bandwidth mainly rests on the attenuation coefficient, and channel capability is affected by the communication range and attenuation coefficient. Ultraviolet communication system is sensitive to system geometry configuration and has very narrow bandwidth and severe inter symbol interference. It is suitable for low bit rate, short range and secret communications.

Optical interferometer extinction ratio determines the sensitivity of interferometric fiber optic sensor system to a large extent and further determines the range of applications and prospects of interferometer. The outline of the current ultra-long distance optical fiber interferometric sensing system development status, the theoretical analysis of the impact of polarization on the optical fiber sensing system, and a variety of factors which can affect the polarization are given. The squeeze-type polarization controller based on photoelastic effect is used to tune the extinction ratio of the system by providing radial stress to fiber interferometer arm, to tune system polarization state dynamically, which makes it possible to molerate the extinction ratio of a long-distance optical fiber sensing system at one point. A novel tuning method to tune the sensitivity of long-distance fiber optic sensing system is proposed, and the range of dynamic extinction ratio of tuning is 0.21～11.03 dB.

Target recognition algorithm based on two-dimensional (2D) wavelet transform for laser imaging radar is put forward. Firstly 2D wavelet transform of range image of laser imaging radar targets is made; then singular value feature is extracted from approximate part and detail part, gene algorithm is used to optimize parameters of support vector machine (SVM) intelligently; at last, SVM is used to recognize three kinds of ground targets. Simulation experiment shows that, compared with the method which directly uses singular value feature of range image to recognize targets, the average recogniton rate is raised by 3.2% at high carrier-noise radio (CNR) of 20 dB and average recogniton rate is raised by 6.5% at low CNR of 10 dB in this method, and good recognition is gained.

Among phase unwrapping algorithms, quality guide algorithm adopting fringe modulation as parameter can constrain the error in shadow and abrupt areas from spreading globally. Reliability guide algorithm with second-order derivative of unwrapped phase as parameter can conduct the unwrapping path to orient the most continuous direction. In order to combine the merits of the above two algorithms, a hybrid algorithm based on fringe modulation analysis and second-order derivative guide is proposed. Firstly, the algorithm finds out an optimal threshold, based on which the fringe modulation quality image is divided into two kinds of area, "good area" and "bad area". Within the good area, unwrapping process is implemented by adopting flood algorithm, while in the bad area second-order derivative of wrapped phase guiding method is utilized to conduct the unwrapping path to orient the most continuous direction. Experimental results on the wrapped phase map of projected fringe method and digital speckle pattern interferometry demonstrate the robustness and efficiency of the proposed algorithm.

Crosstalk will lower down the modulation of the output signal of focal plane arrays (FPA), and then degrade the system′s overall modulation transfer function (MTF). With the development of photoelectric devices, using MTF to evaluate the performances of photoelectric devices is becoming more and more popular. Seen from the trend in civil imaging field, MTF will gradually replace typical parameters such as crosstalk and extreme resolution in evaluation of photoelectric devices. And this makes it a dilemma to decide whether to build a dedicated equipment for crosstalk measurement or not. Considering the relation between crosstalk and MTF, their correlation is analyzed qualitatively, starting from the definition and typical measurement method of crosstalk. It is pointed out that the difference between system′s overall MTF with and without crosstalk maximizes at the Nyquist frequency. Based on this, a new method of calculating percentage crosstalk from measured MTF curves of infrared FPAs is got.

A laser far-field energy density distribution measurement system based on CCD imaging is designed, the measurement principles based CCD imaging method is given, and the model of laser energy measurement is simplified under special conditions. The image information of laser energy density reflected by the reflective board is acquired by the CCD camera, and the laser energy data is received by detectors on the reflective board. The laser spot image and the actual energy data gotten by energy detectors are analyzed according to the model of laser energy measurement, the relationship between gray value and energy density is gotten, and then the energy density distribution can be calculated. Experiments show that this system can measure the energy density distribution with less measurement error. The system is simple, reliable, and suitable for far-field energy density distribution measurement under various conditions.

A micro-ablation of polymethyl methacrylate (PMMA) is carried out by CO2 laser. The effect of the process parameters on the depth and width of the channel is further studied. The rule of the process parameters how to affect the groove depth and width is obtained by the experimental analysis. The results show that the laser line energy density has an exponential relation with the channel width. Through the experiment, we achieve the experiental formula about the line energy density and groove width and the decisive coefficient R2 is 0.96. When the line energy density is less than 300 J/m, the depth of ablated channel has a linearity relation with the line energy density, but this relation is deviated for the line energy density over 300 J/m. By the law of conservation of energy, a model about the channel depth and line energy density is set up. At the situation of low line energy density less than 300 J/m, the calculated results agree well with the experiment. At last, with optimization of process parameters, we make a fine biochip with width of 170 μm and depth of 180 μm.

In contrast to its cubic zincblende phase under bulk form, GaAs nanowires usually adopt wurtzite structure. Surface reconstructions of wurtzite GaAs(1010)A and GaAs(1010)B surfaces have been investigated by using first-principles calculations. The results show that Ga-Ga and As-As dimmers are formed on GaAs (1010)B surface with surface energy 63.5×1020 meV/m2, while no reconstructions are formed on GaAs (1010)A with surface energy 40.6×1020 meV/m2. The relaxed GaAs WZ(1010)A surface has lower surface free energy and more stable.

By using microstructured chalcogenide fibers, split-step Fourier algorithm and nonlinear Schrdinger equation (NLSE), effects of centre frequency and pulse width of seed pulse on mid-infrared supercontinuum (SC) generation are studied. The microstructured chalcogenide fibers used here have high nonlinear effect and two zero dispersion wavelengths (ZDW). The second ZDW is in mid-infrared, which is helpful to mid-infrared SC generation. There are marked effects of centre frequency and pulse width of seed pulse on SC generation. In numerical stimulation, seed pulses have different frequencies and durations. Mid-infrared SC generation whose input wavelength is near ZDWs is wider than those far from ZDWs. When keeping peak power invariable, frequency spectrum broadened by pulse width is steady, but the shorter pulse can generate smoother mid-infrared SC.

In order to enhance the sensitivity of an optical interferometer, we deduce the relation between the group refractive index and the optical sensitivity of the interferometer by using slow or fast light material. The relation demonstrates that high optical sensitivity of an interferometer can be got by using fast light material. Under the condition of slow light, absorption area of corresponding material does harm to to weak signal detection, but the condition of fast light benefits weak signal detection.

The factor, categorization and optical statistical characteristics of laser speckle shown in three-liquid crystal on silicon (LCOS) laser projection display system are studied, and a measuring method of laser speckle is analyzed. According to this, an optical method of rotating diffuser to reduce the composite speckle is applied. Through a series of simulations and experiments, the contrast of speckle patterns is reduced to 4.2%, which is acceptable to people′s eyes. So the method of rotating diffuser effectively suppresses laser speckle, which has simple optical structure and is easy to implement.

Ballonet polishing is a new type of flexible polishing technology in the optical polishing. The polishing experiment is implemented on the flexible ballonet polishing device. Three kinds of different polishing layer materials are used in the experiment. Surface roughness and surface defect of the samples of these layer materials are analyzed. The experimental results show that the woolen cloth is a good layer material which can get high processing efficiency, while the velvet material gets low surface defect on polishing sample.

A closed-circuit television (CCTV) monitor optical system is designed by using Zemax. The effective focal length of the system is 5 mm, the F-number and the full field of view angle are 2.8 and 70°, respectively. The image sensor of the lens is 1/2 inch CCD , whose pixel size is 6.5 μm×6.5 μm. To achieve the lens with compact feature in structure and wide field of view, an inversed telephoto system is used. According to the character of CCTV lens, some field currature remains, which can ensure the system has a high resolution. The result shows that 5 spheric lens can meet the requirement. The value of modulation transfer function (MTF) is more than 0.3 within 0.7 field of view (FOV) at the Nyquist frequency, the MTF value of FOV is more than 0.5 at the 1/2 Nyquist frequency. Various components are the spherical mirror, the form are simple, and the structure is compact.

Derivation of unknown parameters or deviation of practical aspheric optic surface equation with surface error are in practical demand for aspheric machining accuracy analysis, optical system imaging quality analysis, and decomposition analysis of optical lenses. Beginning with an analysis of the data format obtained from Taylor Hobson Talysurf, the key technique used for inversion method to derive aspheric equation based on genetic algorithm and measured data is analyzed. Programmable inversion of aspheric equation is given. It is shown that the method proposed is practical.

The excitation properties of the surface plasmons (SPs) excited by the metallic parallel-nanorod and U-shaped nanostructures are simulated under the illumination field conditions of pulse plane wave and circular high numerical aperture focal evanescent field using the finite difference time domain (FDTD) method. Under the illumination of pulse plane wave, the two nanostructures present the same surface plasmon resonance (SPR) wavelength in the visible range. After that, we simulate the excitation properties of SPs excited by the two nanostructures in the fields of the circular high numerical aperture focal evanescent beam with the same SPR wavelength. The simulation results indicate that the U-shaped nanostructure performs the best local field enhancement and far field transmission ability, which can be used to construct a plasmonic tweezer for trapping nano-particles.

The acousto-optic tunable filter (AOTF) is a good prismatic element based on the acousto-optic interaction in anisotropic material. By introducing the working principle of AOTF, the frequency tuning relationship of the applied acoustic frequency in the crystal and the wavelength of the diffracted light is presented, the frequency tuning relationships under different conditions are given, and the function of the birefringence and rotatory property for the TeO2 crystal on the frequency tuning relationship is explained. The regulation how the parameters such as the optical wavelength and the incident polar angle influence the tuning relationship is discussed.

Measuring instruments and principles of cloud, visibility and present weather based on optical technique are introduced. Considerations are mainly taken on correlative techniques, research and development and operational applications. In order to promote the automatic observation of all meteorological elements in our country, some basic theoretical researches should be strengthened, observation model based on multi-sensors and multi-parameters should be proposed, and instrumental principle should be developed.

The principles and characteristics of several major optical fiber sensors which have a good prospect in the radiation environment are introduced. Based on the preliminary experimental results obtained by Brillouin sensor, the radiation effects on performance of several fiber optic sensors, such as optical fiber Bragg grating sensors, Fabry-Perot fiber optic sensors, distributed fiber optic sensors and transmission fiber, have been described. Several different points are briefly analyzed, and the prospects of different fiber optic sensors in the radiation environment are presented respectively.

Some problems in CIECAM02 that have been identified and the solutions are reviewed. Those problems include mathematical failure for calculating lightness, yellow-blue problem and purple problem that result in mathematical instabilities, a gamut mapping, HPE matrix and backward model when the CIECAM02 is used in an ICC workflow. It is showed that proposed solutions need to be verified by various applications and new solutions need to be presented. Color appearance models are still at the process of development.