According to the application of laser, the distribution of the light intensity usually need shaping. The most important element is diffractive optical element (DOE). adaptive-additive (AA) method is applied and ameliorated, which conquer the two bugs of AA method and improve the precision. A procedure of auto selecting parameter is added in the AA method, in order to reduce the workload of designing. Several ways are proposed to solve the possibility appearing of zero in the denominator. At last, a DOE is designed to shape Gaussian light to square distribution light as well as a grid to divide light, and the results are good. Compared with the AA method, the Gauss method shows its merit. All of these prove the feasibility of the AA method for DOE designing.

In November 2008, April and June 2009, field experiments were conducted with 56 and 31 water samples in Taihu Lake and 30 samples in Chaohu Lake. Then the relation between scattering coefficient and total suspened matter concentrations is analyzed. The scattering model for different seasons and different lakes is developed, and the stable specific scattering coefficient of different seasons and lakes is obtained. Stable scattering coefficient spectral model for different lakes and different seasons is established. Then bio-optical model is used to estimate backscattering ratio, then its spectral dependence is discussed. It can be concluded 1) scattering coefficient of Taihu Lake in different seasons and in Chaohu Lake has stable linear relation with total suspened matter concentrations; 2) Taihu Lake in different seasons and Chaohu Lake have a stable specific scattering coefficient, which is about 0.63 m2/g; 3) Scattering coefficient of Taihu Lake and Chaohu Lake has relatively stable spectral model; 4) Backscattering ratio of Taihu Lake in different seasons and Chaohu Lake is independent on spectrum.

The physical quantity describing atmospheric effect on vision is visibility. The definitions of visibility have been diverse in different application areas and scientific literatures. Horizontal visibility was measured routinely in meteorology. There has been no standard visibility definition for slant path vision which is frequently occurred in such areas as aeronautics. Based on the radiance contract between object and atmospheric background the problem on vision through atmosphere is discussed. Definition of horizontal visibility has been clarified. The slant path visibility has been solved based on the radiative transfer equation. The general characteristics of the slant path visibility under model atmosphere are presented, and emphasis is paid on the difference between up-looking and down-looking visibility.

A new type of short-period horizontal geophone is developed for solving the low sensitivity for detecting ground motion caused by S-wave, which mainly constructed with a vibration limit pendulum and a double-grating diffraction system. The working principle of this geophone is introduced. Its feasibility is proved by analyzing the differential vibration equation and frequency characteristic of mechanical model using a new simulation function of artificial ground motion and theoretical studying the diffraction field after superposed gratings. The light intensity on receiving screen is derived by applying Fresnel diffraction theory. The horizontal velocity of ground motion is calculated through putting forward an easy way to determine the relation between fringe frequency and ground motion speed, and record the time when pendulum passes through the equilibrium position based on the symmetric indicative grating. The dynamic range and sensitivity of geophone system that uses 1800 grooves/mm gratings and 4096 fringe subdivision technique is around 144 dB and 136 pm, respectively. Compared with other kinds of geophone, the corresponding parameters of this newly system is improved at least 10〖WTBZ〗%〖WTB4〗, showing its application potential in exploration engineering.

The measurements of the information on the carrier frequency can be realized by the acoustooptic deflection effects. However, when the multiradio frequency signals are simultaneously input to the acoustooptic deflector, the intermodulation between the signals will be generated in the Bragg regime. It causes great difficulties to signal detecting, especially interference from the thirdorder intermodulation is particularly serious. In response to the intermodulation interference coming from the acoustooptic diffraction, the conditions of generating intermodulation, diffraction distribution, and frequency spectrum are discussed on the basis of the principle of the interaction of the acoustooptic diffraction. Through theoretical analysis, the methods and measures by which the phenomenon of the intermodulation can be reduced are proposed. In order to verify the degree of intermodulation interference in the detection of multifrequency signals, a test system is constructed. By way of experimental analysis, the conclusion that the intermodulation interferences can be reduced effectively by controlling drive power of radio frequency (RF) properly to ensure that acoustooptic deflector works in linear regions is drawn, when diffraction efficiency in the effective bandwidth of acoustooptic deflector is fixed.

The coupling between singlecore fiber and dualcore fiber is one of the major obstacles to the further study and application of dualcore fibers. With Gaussian approximation for fundamental mode in fiber, the expressions of energy coupling into either of the two cores, overall coupling efficiency between the two fibers, and the ratio of energy coupling between the two cores are deduced. The quantitative characteristics of mode matching, the distance between the two cores in dualcore fibers, influence of core position on coupling effect, are discussed in detail. Experimental result shows a good agreement with calculated result.

Reflective intensity modulated fiberoptic sensors (RIMFOS) have received increasing attention in the fields of civil engineering for their superior ability of explosion proof, immunity to electromagnetic and high accuracy, especially fitting for measurement applications in harsh environment. A novel functioning prototype of an integrated sensor based on RIMFOS which is used for acoustic sounding over obstruct is introduced. It aims at the integration of optical fibers based sensors into functional probe for extending the capabilities of the portable solutions for the acoustic detection over solid obstructs. According to the laws of wave propagation, the mechanism of acoustic wave transmission between solid medium and acoustic sounding probe is studied and the calculating formula reflecting the wave transfer process was presented. Some details and overview regarding our ongoing efforts are provided. The experimental results show that the developed sensor′s response distortions towards 1 kHz 94 dB sound pressure level （SPL） signal are all lower than 8% in 4 experimental terms including 5 cm wood board, 5 cm concrete prefabricated board, 12 cm brick well and 10 cm concrete prefabricated board.

Recently, total internal reflection photonic crystal fibers are widely used in most supercontinuum generation, but the output spectra cannot be actively controlled. Allsolid photonic bandgap fibers (ASPBGF) with proper bandgap and dispersion can also be used for supercontinuum generation. The scheme is a candidate for controlling the range of supercontinuum generation because ASPBGF can work as a filter, moreover, ASPBGF is in favor of controllable high power supercontinuum generation because the core diameter has little influence on dispersion. The ASPBGF used for supercontinuum generation with a pulse laser at 1.064 μm is designed, and its groupvelocity dispersion, loss and nonlinear coefficient are calculated according to the structure and material parameters. The bandgap is included in the generalized non linear Schrdinger equation (GNLSE) through the loss dependent on wavelengths. The temporal and spectral evolutions of femtosecond pulse in the first bandgap are gained by solving the GNLSE using splitstep Fourier method. The effect of the bandgap on the spectra extension is analyzed by comparing the output with bandgap and the one without bandgap.

Loss characteristics of antiresonant reflecting plastic optical fiber with cobweb structural cladding and its relationships with the structural parameters are analyzed in the wavelength 1.3 μm. The cladding of this optical fiber is equivalent to periodical multilayer films and numerically simulated by asymptotic transfer matrix method. The effects of the number of alternating layers N, the thickness of highindex layer d2 and index contrast n2∶n1 on the loss characteristics are analyzed to optimize the structural parameters. The numerical simulation results show that the mode loss decreases rapidly in the first and reaches a fixed value in the last as the N increases; the mode lesses increase linearly as the d2 increases; the larger the n2∶n1, the lower the loss at the anti resonant wavelength. On that basis, the thickness of the air layers d1 and the radius of the hollow core rco are optimized by simulated annealing optimization algorithm. Finally, by using above optimal combination of the structural parameters N3, d2=2.648 μm, n2∶n1=1.49∶1.0, d1=3 μm and rco=100 μm, the lowest loss calsulated is 0.449 dB/km。

A simultaneous optical signal dropping and cleaning scheme is presented by utilizing fourwave mixing effects based optical logic gate (AND and NOT) in optical fiber. Two synchronized square pulse control signals with inverted intensity, coupled with data stream, produce fourwave mixing effects to implement dropping and cleaning functions. Simulation and experimental results are successfully demonstrated with nonreturn to zero (NRZ) data at 10 Gb/s. The proposal may work at higher bit rate with transparence for operation wavelength and data format.

The white LED radiation model is an important foundation for the design and analysis of indoor visible light communications. Based on the research of the mechanism of photon radiation for white LED, a generalized white LED mathematic radiation model is proposed, which is composed of Lambert pattern and Gauss pattern. And the quantities, weights and directions of patterns are determined by the structure and material of white LED. Using nonlinear regression estimation based on GaussNewton iterative algorithm, the parameters of model matching with all kinds of white LEDs are estimated. Simulation results show that this mathematic model suitable to commercial white LEDs from different manufacturers is easy to calculate, and that all the coefficients of similarity between values of model and those of LED manufacturers are larger than 95%, and that the mathematic radiation model has a high accuracy.

A highpower allfiber supercontinuum（SC） source is demonstrated by splicing a picosecond fiber laser with a homemade photonic crystal fiber（PCF）. The allfiber configuration enhanced the stability and conversion efficiency of the system. The supercontinuum excitated by picosecond pulses in the normal dispersive regime is studied. The supercontinuum broadening process is explained theoretically. The ultimate supercontinuum spans over 1000 nm with an average power up to 4.6 W and a conversion lightlight transfer efficiency of 54%.

Simulated annealing (SA) is a good tool for solving complex nonlinear optimization problem. The development of its parallelism has become the study focus in recent years. An efficient and convergent parallel simulated annealing (PSA) combined with message passing interface (MPI) method is presented for the optimization of diffractive optics elements (DOE). Using an 8CPU parallel computing platform, optimization designs are performed with incident caliber of 310 mm and 20order superGaussian focal spot of 0.4 mm×0.8 mm. The results show that the smoothing effect with the PSA method can be better and the timecost is less than 1/6 than those with serial SA method, which demonstrates the quickness and effectiveness of the PSA.

A new way to generate bottle beam by using annular beam is presented. When annular beam illuminates perpendicularly bottom surface of axicon, bottle beam is generated along the optical axis behind the axicon. Process of generating bottle beam and transverse intensity distribution at different location on optical axis are analyzed by using geometrical optics. Formulas for calculate bottle beam sizes are deduced and the factors affecting bottle beam sizes are discussed. The results of contrast experiment agree approximately with theoretical analysis. Compared with doubleaxicon and axiconlens, this method for generating bottle beam is simple in operation and the optical elements processing is easy, so it is important in applications.

According to the main problems of multiobject video tracking such as objects collision, merging and splitting, a novel multiobject tracking algorithm based on adaptive mixed filtering is proposed. An adaptive background mixture Gaussian model is adopted to obtain the foreground image, and a simple shadow elimination algorithm is also presented, which describes the HSV components with unified weighted forms, and dose not need judge each component one by one, when it judges the pixels of foreground image. When measured values are extracted from the foreground image, a merging algorithm is introduced, which merges divided detection rectangles into one. Then, the detected foreground measured values are associated with the existing objects based on reasoning methods, and the multiple objects are tracked with adaptive mixed filtering. The algorithm combines the mean shift algorithim which meets the demand of realtime request with the particle filtering one with high reliability when objects are blocked. Simulation experiment proves that the algorithm can track multiple objects efficiently, judge appearance and disappearance of objects accurately, and solve the problems of multiobject blockage, merging and splitting.

The selfimaging phenomenon of twodimensional periodic object is studied based on the scalar diffraction theory, and the selfimaging conditions are extended. It is pointed out that if the square ratio of the two period lengths can be expressed as a quotient of two integers, there exist period angles between the two period directions that can achieve selfimaging. On the other hand, if the square of cosine of the period angle between the two period directions is a rational number, it is possible to find a proper proportion of the two period lengths to satisfy selfimaging. Furthermore, the numerical relation between equivalent combinations of period lengths and angles, which describe the same twodimensional periodic object, is analyzed. The analysis can be utilized to determine whether two combinations of period lengths and angles are equivalent. The simulation result agrees well with the discussion.

Axial superresolution effects of superGaussian phase filters are studied in detail. New parameters (T, W) are used to determine the superresolution region of three zones annular binary phase filter through numerical simulations. Axial superresolution effect difference between superGaussian phase filter and annular binary phase filter is discussed on condition of the same parameters. The axial superresolution response of superGaussian phase filters with it′s index is also studied. Compared to annular binary phase filters, the superresolution of superGaussian phase filters has a slight decline. Whereas it′s sidelobes also has a little decrease, energy utilization rate increases.

Modulation is used to scalage the phase unwrapping reliability and it is related to the measured object〖WTBZ〗′〖WTB4〗s gray and shape informations. A novel online threedimentional (3D) shape measurement method based on modulation delamination is presented. While one sinusoidal fringe is projected on the measured object, the deformed patterns with equivalent phase shift are captured as the measured object moves. The corresponding modulation distributions to the deformed patterns can be obtained by Fourier transform profilometry. A modulation delamination method is used to extract a token from modulation distributions as the mask, and the pixels matching can be realized so as to achieve the equivalent phaseshift deformed patterns at the same pixel coordinate. So the online 3D shape measurement is realized. Experimental results show the feasibility and validity of the measurement method.

The speckle elongation effect of speckle pattern produced at the farfield diffraction plane by roughness surface under illumination of polychromatic light can be utilized to measure surface roughness. A roughness measurement of a shotblasted surface by means of polychromatic speckle autocorrelation is introduced. In consideration of the isotropic radial structure of polychromatic speckle pattern, an appropriate digital image processing algorithm is poposed. Several factors affecting the characteristics of the speckle elongation are discussed, which include the determination of characteristic length of local autocorrelation function, the size of local window for digital image processing, and the exposal saturation ratio of speckle image. By capturing and processing polychromatic farfield speckle images obtained from many points on each sample surface, optical roughness index values of sample surfaces with roughness parameter Ra of 0.4, 0.8, 1.6 and 3.2 μm are calculated, respectively. It is shown that the optical roughness index can be used in scaling well the roughness degree of sample surfaces.

A nonlinearity correction method for a homodyne polarized laser interferometer is proposed, which can compensate nonlinearity error for the interferometer in realtime. Because of the parameter errors, adjusting errors of optical components environment disturbing effect, the output signals′ orthogonal characteristic is destroyed, which causes the nonlinearity error. Based on the ellipse fitting principle, nonlinearity error correction method is proposed. It doses a realtime estimation of the interference signal′s parameter characteristics and studies phase correction range that affects the correction error, then fractionizes signal by 16384 subdivisions, then a result with picometer resolution is realized. A correction criterion for realtime nonlinearity correction is proposed. A homodyne polarized laser interferometer and vibration measurement facility are established. The experimental results indicate that the signalnoise ratio of the interferometer with the nonlinear correction is 30 dB more than the one and measurement resolution is superior to 10 pm/Hz1/2.

Until now, no effective solution is proposed to detect the wavefront of a longfocus and largediameter lens. To solve the problem, combining Talbot effect and Moiré fringe, a new method, which utilizes twodimensional scanning to detect the subaper ture wavefront, is proposed. The optical path is improved and a prototype is established after considering both precision and complexity of engineering. In this method, the subwavefront slope is obtained by twodimensional scanning. The wavefront is reconstructed by mode method based on Zernike polynomials and singular value decomposition method. Compared the experimental results with the measurements of WYKO laser interferometer, the method is validated and the precision of the prototype is acceptable in practical applications.

Multipass cells are largely used in absorption spectrometry technique to improve gas detection sensitivity and reduce detection limit. A novel multipass cell is presented by combining both the advantages of traditional Herriott cell and White cell. It employs White cell′s optical threemirrorstructure and Herriott cell′s beam reflection mechanism. The novel multipass cell possesses features of miniaturizable, simple and compact structure, easily adjustable optical path, and stable performance. The new cell with basal length of 20 cm and adjustable optical path from 10 to 100 m is utilized as the gas absorption cell in a tunable diode laser absorption spectrometry (TDLAS) system for high sensitive detection of CO. The detection limit of CO can be further improved down to 10-6 level with the help of digital signal processing technique. The experiment shows the new cell has an important role in absorption spectrometry technique and it can improve obviously gas detection sensitivity compared with traditional multipass cells.

Detection of pork tenderness by hyperspectral imaging technique was proposed. First, hyperspectral images of 78 pork samples were captured by hyperspectral imaging system, and the spectral region is from 400 to 1100 nm. Dimension reduction was implemented on hyperspectral data by principal component analysis (PCA) to select 3 characteristic images. Next, 4 characteristic variables were extracted by texture analysis based on gray level cooccurrence matrix (GLCM), and they are contrast, correlation, angular second moment, and homogeneity, respectively, thus 12 characteristic variables in total for 3 characteristic images. PCA was conducted on 12 characteristic variables, and 6 principal component variables were extracted as the input of the discrimination model. The detection model of pork tenderness was constructed by artificial neural network (ANN), according to the reference results of pork tenderness by WarnerBratzler method. Detection results of ANN model are 96.15% and 80.77% in calibration and prediction sets, respectively. This work shows that it is feasible to detect pork tenderness by hyperspectral imaging technique.

Aiming at solving the problem that the traditional circle detection algorithm is characterized by low detection speed and so is unfit for multicircle detection, a circle detection method based on global searching is proposed. By combining the accumulation of evidence with weighted average, the pseudocenter of a circle produced in the process of accumulation of evidence is classified and analyze, then 3 pseudocenters of a circle kind by kind are rejected and the other circle parameters are computed. The experimental results show that the proposed algorithm is of high efficiency and is not sensitive to the defect of local information. And the detection time will not increase linearly with the numbers of circle and the detection result is better than the traditional random circle detection (RCD) algorithm obviously.

In order to study the ripple phenomena and its causing mechanism on material surface that caused by the laser irradiation, the pulse generated by neodymium glass laser was used to shock the specimen of magnesium alloy AZ91 covered with black paint as the absorption layer. The threedimensional surface measurement instrument is applied to measure the shocked region of the specimen surface after shocking. And the ripples phenomenon is observed in the shocked region from the measurement results. The surface morphology, as well as the distribution of the surface ripples, is observed and described; and the relation between the characteristics of the ripples and the laser energy is analyzed. It can be concluded that the characteristics of the ripples are affected by laser energy. Based on the effects of the plasma to the specimen and the grating effects caused by the mechanism of coherent stimulated light scattering within plasma, the process of generating thermal microdisturbance on the sample surface by coupling the thermal conductivity, the thermal radiation and the laser irradiation is discussed, and then the formation mechanism of the surface ripples caused by the nonequilibrium state of the surface thermal microdisturbance is discussed.

Thermal effect is one of the most important factors to limit the output characteristics of high energy lasers, and the liquid laser has special predominance on heat managements. An experiment on inorganic liquid laser pumped with laser diode at flowing state is carried out, and high repeating frequency laser pulse output is achieved in a long time. The laser spectrum,the laser pulse shape, and the single laser pulse energy are measured. The laser center wavelength is 1052.7 nm, the laser pulse time width is 170 μs, and the maximum single laser pulse energy is about 5 mJ. The liquid laser can continue running more than 10 min under pumping frequency of 400 Hz. The pulse energy will decrease with the pump frequency increasing. The experimental results show that the inorganic liquid laser system pumped by laser diode can avoid heat deposition effectively at flowing state, and achieve high repeating frequency laser pulse output in a long time, which has the potential to develop into newstyle high power and high beam quality laser system, and is worth carring out deeper experimental research.

Experimental results of a highefficiency 2.7 μm tunable laser are demonstrated on a quasiphasematched singly resonant optical parametric oscillator (OPO) in PPMgO\:CLN (5% MgOdoping) crystal pumped by a 1064 nm laser. Theoretical analysis of the PPMgO\:CLN temperature tuning is presented. When the crystal is operated at 150 ℃ and the pump power is 182 W with a repetition rate of 10 kHz, an average output power of 36.7 W at 2.73 μm is obtained with a slope efficiency of 23.7%. The wavelength tunability of 3.0~2.6 μm can be achieved by adjusting the temperature of a 31.3 μm period PPMgO\:CLN crystal from 30 ℃ to 200 ℃. Compared with the results of theoretical analysis, the discrepancy of about 10 ℃ is found in experiment.

An analytical solution is presented to describe the plasmon resonant wavelength of nanoparticles with arbitrary shapes. Calculation and analysis results demonstrate that the peak wavelength of the extinction spectrum for a nanoparticle of a certain material is determined by the shape parameter L only. The shape parameter L is in good fitting with a quadratic function of aspect ratio η, and its quadratic term coefficient a is a parameter that describes the acutance of a nanoparticle: the sharper nanoparticle is, the larger a is, and as a result, the longer the peak wavelength will be. This investigation can be used as a guideline in designing nanostructures for certain applications.

Terahertz (THz) wave modulator is a key element in future terahertz communication systems. Meanwhile, as a new kind of material, the tunable photonic crystal is widely used to fabricate modulators, switches, filters, and other functional devices in optical communication systems. The combination of THz technology and photonic crystal technology provides a new approach to design the novel THz wave modulator. A novel THz modulator based on the twodimensional silicon photonic crystals is presented. The structure of photonic crystals is consisted of the combination of line defects and point defects, and is designed to be the tunable photonic crystals by filling the point defect with 5CB liquid crystal. By applying the external electrical field on the point defect, the frequency of the defect mode of the THz photonic crystals dynamically shifts. Based on this mechanism, the device can modulate the onoff state of the THz wave propagating. The numerical simulating results show that the THz modulator has a modulation depth of more than 30dB, modulation rate of 10 kHz, and a small size, ease to integrate.

A novel method to fabricate twodimensional photonic crystal alloptical switch is reported. Photonic crystal waveguides can be obtained by infiltration of azobenzenedoped liquid crystals into air holes in twodimensional photonic crystals composed of hexagonal lattices of air cylinders. Numerical simulations show that the photonic crystal band gaps are modulated by nematic liquid crystals infiltrated in the air holes. Then the band gap can be controlled easily under the influence of the external optic field. So the results can serve as an alloptical switch. Compared with the tunable method through an external electric field, the technique has the advantages of fast response and low cost.

To raise output power of the sevencore photonic crystal fiber laser, the effective mode area of sevencore photonic crystal fiber must be increased, and strong coupling among cores is needed to ensure the same phase output. In order to analyse the relationship between effective mode area and coupling strength among cores more intuitively, according to characteristics of the intensity distribution of the sevencore photonic crystal fiber supermode, a calculation method of coupling length of sevencore photonic crystal fiber is giren. The effect of structure of sevencore photonic crystal fiber on the effective mode area and coupling length is analyzed with multipolar method and finite difference beam propagation method. Through continuous optimization of the structural parameters, a sevencore photonic crystal fiber with large outer layer air holes and small inner layer air holes is designed. Its effective mode area is 3703 μm2 and coupling length is 13310 μm.

Starting from the Maxwell equations, a set of coupled planewave equations of frequency doubling in the refractiveindex modulated medium is derived, and a solution to the equations is given under the smallsignal approximation. The smallsignal solution, a form composed of Fresnel functions presents a special dephasing structure which is different from the typical sinc function. Analysis shows that the refractiveindex modulated crystal has a larger phase matching bandwidth than that in a normal nonlinear crystal, so possesses larger temperature, phase matching ange and spectral bandwidths; however the total conversion efficiency has to make sacrifice to pay for this enhancement of bandwidths. It should be noted that the dephasing function can be flattened with a suitable modulating parameter, which will lower the sensitivities of the frequency doubling crystal to erratic shifts of working points out of any thermal and mechanical reasons. It is found by a simulation in the high conversion efficiency case, the characteristics of dephasing function are still in accordance with the result from the smallsignal approximation, except rendering a magnitude difference which depends on coupling strength.

Based on the nonlinear propagation model of ultrafast laser pulses, the polarization dynamics of femtosecond laser pulse in silica is numerically simulated. The degree of polarization and the numerical aperture have effect on the ultrashort laser transmission and the pulse compression. Both the critical degree of the laser polarization and the critical numerical aperture are obtained when the refocusing of laser beams occurs. The results show that by the loose focusing, ultrafast pulses with the linear, elliptic and circular polarizations demonstrate various intensity distribution and plasma filaments structure due to the selffocusing effect. In the temporal domain, the circularly polarized laser, compared with the linearly polarized laser, only shows the selfcompression without the pulse splitting. However, by the tight focusing, three polarized lasers tend to the similar propagation property without the obvious pulse compression.

The aberration theory of planesymmetric optical systems recently developed is applied to the merit function of extreme ultraviolet (XUV) grating instrument defined; consequently the merit function can be expressed as a function of optical parameters. This merit function of multiple parameters is optimized with the cooperative coevolutionary genetic algorithms. The optimization program is set up, which is then used to optimize a XUV flatfield spectrograph system; the ray tracing calculations to the optical system are made with the program Shadow. The imaging calculations show that the merit function is a very useful means to optimize the XUV multielement grating instruments.

For improving the collection efficiency of heliostat fields for solar tower power plants, the design and optimization of heliostat field layouts are needed. Based on the nonimaging optical design theory, a new method in which the field boundary is constrained by geometrical aperture of receiver and the efficiency factor of heliostat is proposed. The heliostat can be placed with higher efficiency by this method. The heliostat field layout is regular, which is helpful for the optimization of the configuration. Therefore, the response speed of the design and optimization of the field is improved. By using the Monte Carlo ray tracing method, the mathematical model of the concentration of heliostat field is created. The field configuration is optimized with parameter search algorithm. A new code for the design and optimization of the heliostat field layout is developed under the Matlab environment and validated by using the current PS10 field in Spain. A new heliostat field of 10 MW solar tower power plant which is located in Beijing is designed by using the new code. The mean annual optical efficiency of the designed heliostat field is 64.15% and is closed to that of PS10 field, which comes up to an international advanced level.

With the development of space optical technology, time delay and integration charge coupled device (TDICCD) space camera has been widely applied. TDICCD image sensor not only improves signalnoiseratio(SNR) of the optical system but also makes the optomechanical structure of the camera more compact, but the optical system distortion will affecte image quality, so the optical system design must satisfy the new demand. The optical system distortion which affects TDICCD integral is analyzed. The method of image distortion elimination of space camera optical system is researched. An optical system is designed with distortion correction lens which is characterized by the spectral band of 450~900 nm, focal length of 6000 mm, and F number of 10. The result indicates that the view field angle reaches 1.6°, optical system distortion is less than 0.01%. modulation transfer function reaches 0.50 at 50 lp/mm Nyquist frequency with 0.06 central obscure, and the quality of image reaches the diffraction limit. The designzd optical system can meet the demand for the use of high resolution space cameras, and is suitable for multispectrum, stereo imaging, and stereo mapping camera system which has little distortion.

Structure characters of a dualchannel helmet mounted display （DCHMD） optical system was analyzed. Based on the discussion of the requirements of DCHMD in application, the system′s technical specifications were presented. The offaxis aberration was analyzed and corrected by proper freeform surface at the right place of the optical system. A DCHMD optical system was developed with technical specifications: 40\O×30\O field of view, 15mm exit pupil diameter, 26.4 mm effective focal length, 25 mm eye relief distance, wavelength range 540~560nm, back focal length more than 3 mm and modulation transfer function (MTF) higher than 0.1 at the frequency of 0.88 lp/mrad. This system has a compact size (70 mm×122 mm) and a decent center of gravity, and could be embedded in the helmets.

In order to improve the performance of systems and apply the dynamic display technology, a designing method of light guide plate (LGP) module for direct illumination is presented, one LGP structure based on the method is also demonstrated, and then the simulated results of module indicates the uniformity is larger than 80%, which can satisfy the need of illumination. The simulated result of large LGP made by many modules for dynamic display is showed, and the experiment of light guide plate module is demonstrated.

A continual zoom system, which can be used as the fore objective of the developed hyperspectral imager, is designed, according to the specification and application requirements of the imager. The lens have the advantages of high speed, visible light wavelength range, long effective focal length (EFL) high etendue and imagery telecentricity. The structural selection and the initial parameter calculation are introduced in detail. The designed zoom optical system with mechanical compensation is presented. The zoom ratio is 4×, and the relative aperture is 1∶2. The effective focal lengths are 55 mm and 220 mm respectively at short and long focus end, and the corresponding field of view angles from 2° to 8°. The distortion is lower than 0.6%. The modulation transfer function (MTF) value at the spatial frequency of 66 lp/mm is higher than 0.5. The designed zoom system can meet the application requirements of the hyperspectral imager.

Based on the theory of offaxis threemirror ststem, an optical system with effective focal length of 5000 mm and field of view of 5° is designed. The image qualities of this system are near diffraction limit. Some factors in practical engineering application are taken into account in course of design, so that this system is very useful in the field of space optical remote sensing.

Effects of external cavity′s feedback light on length of internal cavity and the photon state density in internal cavity are investigated, and effects of self mixing interference are discussed in detail. The results demostrate that, external cavity′s feedback light not only changes front facet reflectivity of FabryPerot cavity, but also cause discontinuous variation of equivalent length of internal cavity, and then photon state density in internal cavity also discontinuously varies. So that, the external feedback light makes quantum efficiency continuously and discontinuously vary. Also gain coefficient and saturated light intensity vary continuously and discontinuously. Also selfmixing interference signal does not change discontinuously with the complex cavity modes produced by external cavity′s feedback light, and effect of external cavity′s feedback light on charge carrier lifetime is very small. External cavity′s feedback light evidently reduces radiative recombination lifetime of charge carrier, raises radiative recombination efficiency and weakens nonradiative recombination efficiency.

A nearinfrared (NIR) polarizing beam splitter is designed based on a single layer subwavelength silicon grating, which is reflective for TE polarization and transparent for TM polarization around the incident angle of 45°. The design of the proposed beam splitter is based on the leakymode resonance effect and Brewsterlike effect of the subwavelength grating. Scattering matrix method and finitedifference timedomain method are utilized to design and analyse the structure. Simulation results show that both the reflection and transmission extinction ratios of the beam splitter are over 100 in the wavelength range of 1390~1600 nm. Moreover, the polarizing beam splitter has a relative big angular tolerance and the efficiency of the beam splitter under the illumination of a Gaussian beam with finite size is very high.

An accurate theoretical method based on matrix optics and diffraction theory is developed for predicting the performance of the extremely long compound refractive Xray lens. The size of focus, effective aperture of focusing Xray beam and the intensity gain in focus are derived. Then several PMMA extremely long parabolic compound refractive Xray lenses with the curvature radius of 50 μm are fabricated by means of deep Xray lithography. Finally, the focusing performances of the PMMA extremely long parabolic compound refractive Xray lenses are measured and analyzed under 8 keV monochromatic on the 4 W, 1 A beamline of Beijing synchrotron radiation facility (BSRF). According to the experimental results, it is shown that the PMMA extremely long parabolic compound refractive Xray lenses promise a good focusing performance under hard Xrays.

Charge coupled device (CCD) is a pivotal module of imaging system. The point spread function (PSF) of CCD is an important part of the PSF of imaging system. A backilluminated , partially depleted CCD is studied. The movements of the carriers in the CCD are analysed. The PSF are simulated based on MonteCarlo method. The simulative PSF can well match analytical PSF which are also computed. The main characteristics of CCD are analyzed，such as responsibility,linearity and modulation transfer function. The influences to PSF caused by the change of wavelength and fieldfree region are simulated, which show that better PSF can be attained by smaller fieldfree region or longer wavelength.

Using RichardWolf vector diffraction integral formulae，the radial，azimuthal and longitudinal component expressions of the focused threedimensional light field of radially polarized highorder vector BesselGauss beams by an objective with primary spherical aberration and obstructed by an aperture are obtained. The effects of primary spherical aberration on the focused light field distribution by the objective obstructed with a circular aperture and an annular aperture are numerically simulated. It is shown that, the influence of spherical aberration on the light distribution at the focal plane is very small especially for the case of the objective obstructed with an annular aperture. In the case of an objective with spherical aberration and obstructed with a circular aperture, the focused light fields before and after the focal plane are not symmetrical. The intensitydistribution change of each point at the focal plane resulted by spherical aberration does not uniformly increase or decrease. The size of the light spot at the focal plane focused by an objective obstructed with an annular aperture is much smaller than the one focused by an objective obstructed with a circular aperture.

By means of PeggBarnett phase formalism, the phase properties of the field interacting with more Λtype threelevel atoms via Raman coupling in a phase damped cavity are investigated. The influences of decay coefficient of the cavity, the intensity of the field and the number of atoms on the phase distribution as well as its fluctuation are discussed. The results show that if there is absence of the phase damping, the phase distribution oscillates with the period π/λ. It presents a structure of single leaf at t=nπ/λ, but it splits into multileaf structure during the evolution period due to the interaction between the field and the atoms. If there is presence of the phase damping, the obvious leaf structure of the phase distribution becomes obscure and contracts into a circle, which indicates the random distribution of the phase. The larger the decay coefficient is, the more rapidly the phase becomes random distribution. Otherwise，the change of the number of atoms does not affect the leaf structure of the phase distribution, but intensifies the oscillation of the phase fluctuation.

The ground state properties of the strong coupling bipolarons in a parabolic quantum dot are studied based on the LeeLowPinesHuybrechts variational method. The law of the effective potential Veff of the strong coupling bipolarons changing with the strength of the electronphonon coupling α, the relative distance between two electrons r, and the radiu of quantum dot R0 are derived. The results show that Veff consists of three parts: Coulomb potential Vcoul, confining potential Vconf and induced potential Ve-LO. Ve-LO is always less than zero, and the absolute value |Ve-LO| increases when the strength α, and increases when the relative distance r between the electrons and guantum dot′s radius R0 decreace. The absolute value |Veff| increases with the strength α increasing and increases with the relative distance r decreasing. α and r are the main factors to influence the effective value. However, the quantum dot′s radius R0 and the dielectric constant ratio η have little influence on the effective potential Veff.

It has the application potentials of standoff detection of biological aerosol by passive infrared remote sensing based on Fouriertransform infrared (FTIR) spectroscopic technique. There are often noise signals and baseline drift on the target spectral signature in infrared remote sensing measurement. The spectrum of biological aerosol is relatively broad and the traditional methods of baseline correction are inapplicable. Due to infrared spectra of biological aerosol and different baseline drift are nonGaussian signals, an algorithm for preprocessing infrared spectra of biological aerosol is devised based on independent component analysis (ICA), where nonGaussian is used as independent measure. The results of experiments show that this algorithm can separate unknown interference and baseline drift as independent component, and with no effects on the further qualitative and quantitative analysis.

The light scattering and radiation characteristics of space target is related to its background environment, geometric structure and surface material, and also influenced by its attitude variation. The influence is especially prominent in spacebased surveillance. The influence of attitude variation on visibleradiation characteristics of space target is modeled on the basis of orbit theory, and the irradiance variation with attitude of HJ1 and ZY2 satellites is calculated by the given parameters. The calculation results indicate that the influence of attitude variation is not neglectable. The research could provide theoretical basis for space target detection and recognition.

The monochromatic synchrotron radiation spectra of spherical grating monochromator (SGM) working in soft Xray and vacuum ultraviolet (VUV) region are often contaminated by significant amount of higherorder harmonics. They cannot be suppressed completely even by suitable filters. Higherorder contributions in the spectral radiation standard and metrology beamline are researched by using transmission grating (3300 lp/mm made in house) and IRD AXUVI00G (USA) photodiode detector. The exit beam is dispersed with the transmission grating behind exit slit of the monochromator, and the contributions of the different orders are analyzed. In wavelength region between 5 nm and 34 nm with proper Al, Si and Zr filters, the contributions of higherorder intensity are less than 8.06%. After modified by quantum efficiency of the detector, the higherorder contributions are restricted to less than 3.08%. In wavelength region between 35 and 40 nm with Al/Mg/A filter, the higherorder contributions are restricted to less than 10.00% after modified by quantum efficiency of the detector.

As a speedy analytical technique of chemical compositions, laserinduced breakdown spectroscopy (LIBS) is appealing in metallurgical industry for insitu, online or longrange applications. Combined with LIBS, neural networks are used to calibrate and quantify the concentration of Mn and Si of different kinds of steels. The performance of the neural networks with different inputs is studied. Compared with the common internal calibration methods, neural networks can utilize more information of spectra, and better correct the matrix effect and line interference. The inputs of the neural networks, however, need serious consideration, since they have a great effect on the measurement reproducibility and accuracy.

To shield the detection radar wave for radar/infrared combined guidance weapons, an idea of designing a kind of combining frequency selective surface (FSS) coatings is proposed on ZnS substrate. The coatings are not only infrared transparent, but also have bandpass properties in radar wave band. An inductive mesh which is treated as the initial structure is designed and analyzed. An FSS structure with aperture element of cross shape is designed and analyzed by a socalled Galerkin′s method in the spectral domain. The resonance frequency of this FSS structure is 31.75 GHz, whose transmittance is about -0.38 dB. The resonance frequency of FSS on perfect conductor (PEC) surface which has the same parameters is 33 GHz. Antireflection coatings are designed by optical coatings theory with two coating materials to improve the infrared transmittance of this combination structure. The total layers′ thickness is 1.085 μm. The sample is fabricated by depositing coatings and lithography. The test results indicate that the transmittance at radar central resonant frequency of 31.5 GHz is about -0.63 dB, and the average transmittance (out of central frequency) is lower than -7.51 dB . The average transmittance is 87.95% in longwave infrared region.