In the procedure of retrieving aerosol backscatter coefficient,the boundary value of aerosol backscatter coefficient is always assumed around the troposphere to eliminate the lidar constant. When the range of the lidar detection cannot reach the tropopause,it is very difficult to determine the boundary value. A relationship between boundary value and range square corrected signal is derived from elastic scattering lidar equation. Using this relationship as a criterion,a boundary value can be determined in the lower troposphere with iteration algorithm. A profile of aerosol backscatter coefficient ,which is retrieved with the boundary value determined using a new method introduced in this paper,is compared with the one retrieved with the boundary value assumed around the troposphere. The comparison shows that these two profiles seem to be consistent with each other well. The profile of aerosol backscatter coefficient can be retrieved with the boundary value determined using the new method in the lower troposphere.

The basic principle of Mie Doppler lidar for wind measurements is introduced. The structure of self-developed Mie Doppler lidar system is presented. Comparing experiment with a wind profiler is conducted. The horizontal wind speed and direction data from those two instruments show good agreement. From 0.55 to 2.4 km altitude,the average errors of horizontal wind speed and direction are 1 m/s and 7°,respectively. The example of continuous wind observation is given,and the dynamics of wind field is analyzed. The above results indicate that measurements on this Mie Doppler lidar system are reliable,and can be employed for the routine observations and analysis of low tropospheric wind. The space distribution of line-of-sight wind speed and horizontal wind profile are obtained by using PPI scan mode,which indicates that,the system may have the capability of wind shear and clear air turbulence detection.

The analytical expressions of the far-field divergence angle,the beam width and the M2-factor in rectangular coordinate systems for laser beams propagating in atmospheric turbulence are derived by using the extended Huygens-Fresnel principle and the definition of the second moments of the Wigner distribution function. Taking the elegant Hermite-Gaussian (EHG) beams as typical examples of laser beams,the propagation properties of the EHG beams in turbulence are analyzed quantitatively. It can be shown that the M2-factor of the laser beams in atmospheric turbulence is related to the M2-factor of the incident plane,the second moments of the incident plane,the propagation distance in turbulence,wavenumber and the influence factor of the atmospheric turbulence. Specially,the far-field divergence angle,the beam width and the M2-factor of the EHG beams increase with the propagation distance in turbulence. And the influences of the atmospheric turbulence on the far-field divergence angle angle,the beam width and the M2-factor of the EHG beams with higher beam order are smaller. The M2-factor of the EHG beams depends on the propagation distance,the structural constant of the refractive index fluctuations of the turbulence,the wavelength,the beam order and the waist width of the fundamental-mode Gaussian beam.

There is a spectral transmission peak between 1107 and 1108 absorption lines of iodine. The spectral transmission peak can suppress the atmospheric Rayleigh backscattering,while affect weakly on the atmospheric Mie backscattering. The high spectral resolution lidar,in which the above iodine filter acts as the ultra-narrow band filter to the Rayleigh and Mie backscattering signals,can measure the atmospheric backscattering ratio and wind field. The measurement theory is deduced and simulated by using reasonable lidar parameters and atmospheric models. The simulation results show that for the atmospheric backscattering ratio measurement,the precision is 5% for altitude lower than 25 km at night and 8 km in daytime. For the line-of-sight wind velocity measurement,the measuring range is ±40 m/s and the precision is 5% for altitude lower than 5 km at night and 4 km in daytime.

Four pieces of reflection volume phase gratings are selected,and then divided into two groups,in which the fringes are orthogonal to each other. The planes of grating′s vector of each group are perpendicular to each other. As a result,a two-dimensional low-pass spatial filtering for continuous-wave (CW) laser beam is achieved. Based on Kogelnik′s coupled-wave theory,the performances of that configuration of filtering for CW laser beam are analyzed,and the filtering characteristics of the configuration for deformed Gaussian laser beam are simulated. The results show that the components with high angular frequency of the input laser beam have lower diffraction efficiency,while those with low angular frequency have higher diffraction efficiency up to 98% in this configuration. The high angular frequency can be filtered out from the laser beams without focusing. The spatial intensity distribution of filtered laser beam is similar to that of undeformed one.

Based on the volume grating coupled wave theory,temporal and spectrum expressions of a non-absorption transmission volume grating read out by a femtosecond pulsed laser beam are deduced. Then their changes with the refractive index modulation are discussed. It is showed by numerical simulation that,when the refractive index is increasing in a certain range,at first the temporal diffracted pulse will be one,then the center of the pulse will decrease and split into two pulses,then into three pulses. If increasing the refractive index modulation further more,the number of pulses will return to two,then to one. The above processes will be repeated if the refractive index modulation increased to another certain level. Moreover,if the refractive index modulation changes from 1.0×10-3 to 1.0×10-2,the interval between two diffraction pulses will increase with the increasing of the index. And the simulation of the changes of diffraction intensity spectrum with the refractive index are also mode.

Aiming at polarization-induced signal fading phenomenon generally existing in interferometric fiber-optic sensor,the principle of polarization diversity receiver (PDR) is theoretically introduced and demonstrated by simulation. Experimental sensing system of fiber-optic Michelson interferometer based on phase generated carrier (PGC) is designed and set up. An all-fiber tri-cell polarization diversity receiver is designed to receive the signal from the sensing system. The demodulated signal is in good accordance with the simulation signal produced by a piezoelectric phase modulator in one arm of the interferometer. The fringe visibilities obtained from the three output-channels of PDR are observed with the polarization state of the interferometer changed by twisting the fiber of the interferometer. The relationship of the signal stability,self-noise of the system,and fringe visibility are obtained. The results show that polarization-induced signal fading can be inhibited by selecting an output-channel of PDR with the fringe visibility higher than 0.5.

The process and principle of stimulated Brillouin scattering(SBS) signal generation are analyzed. A novel ring configuration for generating high-order Brillouin scattering signals is proposed. The first-order to sixth-order Stokes signals are obtained by the experiment. Based on this new method,the sideband signal modulated by Mach-Zehnder modulator(MZM) is selectively amplified by the gain spectrum of the corresponding fourth-order Stokes signal. Finally,the amplified signal is beat with the optical carrier signal to generate a high-frequency microwave signal. This technique can be utilized to generate microwave signals with frequency of n (1≤n≤6) times of 11 GHz using only one erbium-doped fiber amplifier(EDFA). This method has the advantages of low cost and high efficiency of frequency multipling. The feasibility of this method is demonstrated by simulation and experiment.

A novel experimental scheme is reported about double wavelength decision using optical fiber parametric amplifier in a highly nonlinear fiber (HNLF). So multi-channels signals can be reshaped and regenerated simultaneously. This scheme is based on a coil 500 m HNLF. The input signals are two channels of 10 Gb/s return-to-zero (RZ) pseudorandom bit sequence with different wavelengths,and the pump is clock pulse with 10 GHz frequency. Parameters process of signal and pump occurred at HNLF,two idlers are filtered through two different center wavelength optical band pass filters,then the all-optical decision is realized. In the experiment,two channels of 10 Gb/s RZ are firstly deteriorated for simulating the long-haul transmission loss and distortion. The extinction ratio (ER) of deteriorated signal is respectively 9.17 dB and 8.27 dB,and the ER of decision signal is 12.8 dB and 12.66 dB. A scheme of dual wavelength all optical decision is demonstrated through the experiment.

A design for a novel broadband mode converter based on an asymmetric dual-core photonic crystal fiber is proposed. With adjusting the air-hole diameters of the inner rings in the cores and the index of the down-doped silica rods,broadband index-matched coupling is achieved. Numerical investigations demonstrate that a novel mode converter with operating wavelengths ranged from 1.45 μm to 1.61 μm at the loss of 0.5 dB and polarization-dependent loss which is lower than 0.28 dB can be realized in a fiber with a length of 5.9 mm

A 40 GHz radio-over-fiber (ROF) system is investigated experimentally to generate optical millimeter wave with optical orthogonal frequency division multiplexing (OFDM) signal using an optical phase modulator or an optical intensity modulator, and the transmission performances of optical millimeter waves are compared. In the central station, the 2.5 Gb/s OFDM analog data and a 20 GHz radio frequency (RF) clock are mixed to drive an optical phase modulator or an optical intensity modulator to realize the double-sideband (DSB) modulation, generated optical millimeter wave with OFDM signal, transmitted to the base station over standard single-mode fiber(SSMF). In the base station, the optical millimeter wave signals are converted to electrical signals after optical-electrical conversion, and the down-converted OFDM signals are detected after mixed with the local oscillators, and the optical carrier filtered out by a fibber Bragg grating (FBG) can be used to realize wavelength reuse. Effect of different peak-to-average power ratios on bit error rate (BER) is demonstrated experimentally. The results show that under the high optical power, after transmission over 50 km SSMF, the power penalty for the optical millimeter wave generated by an optical phase modulator and an optical intensity modulator are less than 0.5 dB and more than 1 dB, respectively. It demonstrates that the fiber transmission quality of optical millimeter wave with OFDM signal generation using an optical phase modulator is better than an optical intensity modulator.

A highly sensitive humidity sensor based on Fabry-Pérot (F-P) interferometer which is formed by hollow core fiber with low sensitivity to temperature is realized. Because the optical path difference of interferential cavity depends on the cavity length and the refractive index of the media which is filled in the F-P cavity. The F-P sensor is filled with a novel nano-composite hydrogel with a strong water capacity. It is realized that the humidity can be measured by measuring optical path difference of the sensor when the refractive index of hydrogel changes due to absorbing water vapor in the air substantially. The experimental results show that the optical path difference changes from 608.7180 μm to 604.0488 μm when the surrounding humidity varies in the range of 38%-98% and the sensitivity of optical path difference versus the relative humidity is 77.82 nm/(1%).

By using effective index method to calculate the transverse refractive index distribution of polymer rib waveguide,3D lightwave propagation is successfully simplified into a 2D one. Starting from the scalar wave equation,the one-step restriction on beam propagation is obtained by exploiting the slowly varying envelope and the paraxial approximation. The recursive formula is deduced using the series expansion of exponential differential operator,and the basic computing scheme is derived from the differential approximation. Considering the similar transformation of the symmetric matrix,the calculation speed of this algorithm is greatly improved. Based on the algorithm,the propagation characteristics of the TM lightwave in the Mach-Zenhder (M-Z) waveguide are systematically analyzed,including optical loss and the effect of structural parameters such as rib width,Y branch angle on the insertion loss. It is demonstrated that the operator expansion beam propagation method can be applied for the theoretical analysis and design of polymer M-Z waveguides with high precision,small computation complexity and high efficiency. The approach provides an alternative method for the design of polymer electro-optic modulators.

A novel double Sagnac distributed fiber-optic sensor based on Sagnac interferometer for determining the position of disturbance along an optical fiber is presented. The configuration and operating principle of the system are illustrated,and the location principle and method for the detection system are analyzed. The system realizes the location of disturbances by using the adaptive time-delay estimation with the least mean square (LMS) algorithm in the time domain. Theoretical analysis and experimental results show that the proposed technology can realize the detection and location of the disturbed signal rapidly and effectively. This method is simple and can be obtained easily,and it has high measurement sensitivity and location precision. The maximm location error is less than 20 m.

All-fiber Fabry-Pérot based on ring reflector structure is fabricated by orderly splicing two section of hollow fibers with different core diameters to the light induced single-mode fiber. As the small hole in the ring surface is easy for gas or liquid in and out the cavity,it is useful in detecting the refractive index of gas and liquid. The forming theory of the fiber optic Fabry-Pérot cavity is analyzed,and the refractive index sensor base on ring reflector is studied by experiments. A resolution of the refractive index 1.652×10-6 is obtained in a measuring refractive index experiment. It can be anticipated that the Fabry-Pérot refractive index sensors with ring reflector will have important applications in the fields of the toxic,flammable,explosive gases and low viscosity liquid refractive index or content detection.

PMPS-PBzMA copolymer is prepared using PMPS/BzMA with different mass ratios,the methods of controlling film thickness by spin-coating and the best heat treatment temperature are studied. Near-infrared spectroscopy confirm that the material′s absorption is low in the 1310 nm and 1550 nm communications windows. Experiments show that the photobleaching effect of PMPS-PBzMA is mainly due to the Si-Si photo-oxidation,and accompanies by a slight refractive index anisotropy. Reduction of refractive index in saturation process is due to the Si-phenyl-light decomposition,and this process will alleviate the anisotropy. Experiments summarize in the relationship among the initial refractive index,the saturation refractive index and the PMPS/BzMA mass ratio,and find out that the initial refractive index of material prepared using W(PMPS):W(BzMA)=10% and the saturation refractive index of material prepared using W(PMPS):W(BzMA)=100% are approximate. According to these features,using initial refractive index of W(PMPS):W(BzMA)=10% material and saturation refractive index of W(PMPS):W(BzMA)=100% material and photobleaching techniques,multi-mode embedded waveguides are successfully fabricated,the propagation loss in a channel waveguide is 0.91 dB/cm at a wavelength of 1310 nm.

The design of an axicon-liked cemented doublet-lens system (lens axicon) made of two spherical aberration lenses through controlling and optimizing the spherical aberration of the surface is presented. The lens axicon has the main Bessel beam properties. Compared with axicon,this element is inexpensive and easy to manufacture even with large apertures. The evolution of the generated Bessel beam using lens axicon is simulated by using optical-design software. In the experiment,the Bessel beam patterns are captured in different propagation position. And the experimental results fit well with the theoretical simulation.

The aplanatic parametric equation,that describes the one-one correspondence relation of ray parameter and coordinator,is established with the aperture height of the incident light as the variant,based on the aplanatic principle and ray tracing method. The intersecting line of aspheric meridional ray presented by the equation is a continuous real curve since the parameter is also a continuous real variable. The rotating surface of the intersecting line is an aplanatic refraction surface. Meridional intersecting line is a high-order curve of the aperture height. The parametric quadratic equation in two variables refers to the convergent emergent rays and in one variable refers to the parallel emergent rays. Without analytic hyperbolic curve or high-order correction item,this parametric equation can realize zero spherical aberration design for the curves with multi-turning points,such as long focal distance system,large aperture system and Schmidt corrector.

In optical information processing,the very tiny differences and minutiae in an image can be enlargeded by the image derivations and pseudo-color codes,which have different advantages. In this paper,combining the two methods,a new method is proposed. Firstly,an image is coded by a grating Secondly a white light sourse is used,and the space frequency of the image is filtered in 4F optical system. Then the image derivations and pseudo-color codes on an image with successively changing greyness are realized simultaneously.The proposed method with changeable derivation can process large areas and offer rich color image. With this new method,the pictures such as the CT pictures are easily analyzed forexample.

A nonlocal image inpainting model is proposed by incorporating the nonlocal differential operators into the curvature-driven diffusion model. The new model differs from the original model in that pixels of similar structures rather than pixels in the local neiborhood (the case for the original model) are utilized to estimate the lost pixels. This difference makes the new model perform very efficiently in inpainting images,especially textured images.

Compressive sensing (CS) is a novel signal sampling theory under the condition that the signal is sparse or compressible. It has the ability of compressing a signal during the process of sampling. Reconstruction algorithm is one of the key parts in compressive sensing,and it is of great significance to verify the sampling accuracy. In this paper,properties of the existing reconstruction algorithms are firstly analyzed. And then a new variable step size adaptive matching pursuit (VssAMP) algorithm based on greedy pursuit is presented by introducing an idea of variable step size. The proposed algorithm could control the accuracy of reconstruction by both variable step size and double thresholds although the sparsity of a signal is unknown. The experimental results show that the proposed algorithm can get better reconstruction performances and is superior to other algorithms both visually and objectively.

The closely spaced objects (CSOs) create blur imprints on infrared focal plane,which make it necessary for information processing to have a super-resolution. Objects′ imaging on infrared focal plane is modeled,and a super-sesolution objective function based on least square criterion is presented. Traditional optimization methods have to be carefully initialized otherwise they will get poor estimation performance and suffer from large computation load. So a particle swarm optimization (PSO) algorithm is introduced to optimize the super-resolution objective function,and jointly estimate the projection position and radiant intensity of targets on the focal plane,then realize the super-resolution of CSOs. Simulation results show that the least square-based PSO algorithm gains superior performances than that of the traditional steepest descent method and possesses the better capability of super-resolution.

In order to improve the imaging quality of modified super-widen-angle Sagnac imaging interferometer (SASI),the modulation transfer function (MTF) fMTF is investigated. After calculating the five boundary conditions of incident ray of the modified SASI,its pupil function is given. Then,the expression of MTF of the modified SASI is deduced according to Fourier transform. Using the relevant parameters of optimized SASI,the curve of MTF is drawn and the result is fMTF=0.62 at Nyquist frequency. But the fMTF of WINDII (Michelson imaging interferometer) which is used to measure the upper atmosphere wind field is 0.35. It shows that the SASI has a better imaging quality than WINDII.

A model is built from the infrared remote sensing radiative transfer theory and the two stream approximation for passive infrared detection of biological aerosol,which theoretically illustrates the effect of scattering of radiances from all sides incident on the aerosol. The laboratory principal experiments are conducted on a microorganism spores aerosol for studying the infrared spectral properties of biological aerosol. The results of preliminary laboratory experiments in bioaerosol cell are presented,and the experimental phenomena are explained with radiative transfer model. It is shown that the detection model are effective and reasonable. Combining the detection model and the laboratory experimental results can give a reference for field passive standoff detection experiments of biological aerosol.

The study of mechanical property about low-dimensional materials with its wide application has been one of the hot-spots. In the real-strain measurement of low-dimensional materials,the tracking target on the surface of large distance specimen would move out the scope of image tracking. In this way,the tracking target might be lost,which affects the real-strain measurement. So the optical extensometer based on digital image tracking technology is proposed to change the large distance to small one. Then,the tracking objective is adjusted to move in the screen field of view. The method of real tracking can be realized. Moreover,the strain regulation of low-dimensional materials might be dynamically learned. The strain measurement is carried out using micro-mechanics universal testing machine and optical extensometer together. From the experiment,the results obtained by the optical extensometer are agreed with ones obtained by the micro-mechanics universal testing machine. And,the objective is orientated in the 0.01 pixel location using the arithmetic of bilinear inter value. So,the optical extensometer can be applied on the real-strain measurement of low-dimensional materials. Also,a new experimental method is offered for studying the dynamic mechanics of low-dimensional materials.

The mapping between segments and control sites is an important factor that influences the correction result of model-based optical proximity correction (MB-OPC). The existing mapping schemes are rule-based and it is either the inaccurate one-to-one mapping or the time-consuming all-to-one mapping.A new MB-OPC with model-based mapping between segments and control sites is proposed. The mapping model is a charasteristic area derived from gradient of intensity,and it can be a one-to-one mapping or a multiple-to-one mapping. The mapping can be applied to all the control sites in MB-OPC,and there is no need to recalculate repeatily. The experimental results show that the variance of edge placement error (EPE) of MB-OPC with model-based mapping is significantly improved and the run time is not significantly increased.

Two-dimensional (2D) wavelet transform is applied to phase analysis of spatial carrier-fringe patterns. Hilbert transform is firstly performed on carrier-fringe patterns to get the complex signals,in which the phase information is included. And then two-dimensional wavelet transform is carried out on the signals. Finally,the phase information demodulated by the height of object can be gotten from the wavelet transform coefficients at the wavelet ridge position. The result performs better than that of one-dimensional wavelet transform method,especially when there is much noise in the fringe patterns. Computer simulation and experiments verify the validity of the proposed method.

Knife-edge method is one of the main methods to obtain the modulation transfer function (MTF) of X-ray detectors,while data processing is critical to the accuracy. A series of data processing methods is presented,which can improve the measurement accuracy of MTF for a high-resolution X-ray CCD. Before experiments,MTF simulation is employed to predict the curve trend and noise level. Subsection-analysis algorithm is used to analyze the curve fluctuation in order to eliminate the subjective errors. MTF is recorrected by the oblique angle of the knife edge,which is gotten by using self-adaptive algorithm,clip-window algorithm,and Hough transform. After all the procedures,the mean square deviation of 0.011 for the MTF is achieved,while the Nyquist frequency error is 2.52%.

Computer-aided alignment (CAA) is an effective method to improve the imaging quality of high-precision,complex,and off-axis optical systems. A computer-aided alignment method for off-axis reflective zoom systems is proposed. Due to the varying optical characteristics of a zoom system,sensitivity matrices are used in the alignment rather than a single matrix. Thus,the computer-aided alignment of a zoom system can actually be considered as a series of independent alignments of with different configurations. Each alignment in this series includes the calculation of sensitivity matrix and difference in aberrations between the actual system and the designed system,and the determination of misalignments. For this purpose,a new mathematical model is established. By numerical experiments and comparison of the image qualities between the pre-aligned and post-aligned systems,the feasibility of the CAA method is demonstrated.

The scattering pulse signal counting distribution generated by the irregular particle is the full reflection of particle size distribution. On the basis of two parameters-amplitude and width,the statistic characteristic of the random pulse signal is studied. The laser particle counter photoelectric sensor is used to measure the amplitude and width of the scattering pulse signal which is generated by the aerosol particles in air. The experimental results indicate that the statistical distribution of the pulse signal is not axis-symmetrical but lognormal distribution which is a specific exhibition of the random effects in measurement. It shows that it has fractal structure relation among the characteristic parameters of the non-spherical particles. In particular,the fractal dimension is the statistical dispersion′s ratio of the amplitude and width of the scattering light pulse.

A three-dimensional amplifying model for the laser system is presented. Both free space transportion model and ray-tracing amplification model are included in this model. Using the model,the distribution of output laser beam from a complicated amplifying system close to the reality can be obtained. This model is used to simulate an amplification course in a 12-pass laser diode-pumped amplifying system. Simulation results precisely show the output distribution of the laser beam from the 12-pass amplifying system. Based on the simulation results,the 12-pass beamline can be further optimized.

Taking InGaAs/GaAs strained quantum wells as an example,the 6×6 Luttinger-Kohn Hamiltonian considering the valence band mixing and the wave function mixing,and by using the finite-difference method to solve the Luttinger-Kohn Hamiltonian of the effective mass equation are introduced. Then the conduction-band structures and the valence-band structures are obtained. The transition matrix element of strained quantum well,and the material gain with linear Lorentzian function are also calcuated. Finally the well width,carrier concentration,temperature and other factors which influence the gain material are discussed. The results show that the compressive strain makes the effective quantum well bandgap increase,reduces the transparency of the material gain current density,and then lower the threshold of the device to improve the output characteristics of the device. The right deviation between the gain peak wavelength and the emission wavelength make optically pumped semiconductor laser′s threshold current and operating current have small changes in temperature.

The research on startup null drift performance of four-frequency differential laser gyro is very valuable to the fast startup situation. Based on the process of warming-up,physical mechanism were analyzed,some affecting factors of null drift were discussed,and then the corresponding solutions were introduced. For example,we adopt dispersion equalization technology to decrease the sensitivity of gyro drift to frequency stabilizing position,auto-gain control loop to stabilize the light intensity,space non-planar cavity structure to eliminate the effect of quartz crystal,suitable design of thermal arrangement to speed up the heat balance process,reliable detecting circuits to enhance the stability,related measures to minimize the cavity distortion and so on. Experimental results show that these solutions are effective to improve the startup null drift performance of laser gyro,which are helpful to researchers.

In connection with the infrared target detecting under complex backgrounds,a detecting algorithm based on symmetrical displaced frame difference (DFD) and optical flow estimation is put forward. Firstly,through using symmetrical DFD algorithm on infrared sequence frame,possible target areas are extracted by using frame difference (FD) algorithm and auto-adaptive segmentation of threshold. The area is extended and piled up,then the possible target area is gotten in continuous frames. Secondly,every infrared frame′s optical flow field is calculated,and through threshold segmenting and combined mathematical morphology algorithm targets are detected in areas. This method can sufficiently utilize the advantages of little calculation of symmetrical DFD algorithm and high exactness of optical flow detecting method. So it can cut down the calculation as well as satisfy the veracity. The experimental result shows that this method works perfectly and can effectively detect infrared targets under complex backgrounds.

Target model drift is an important factor for visual tracking. To deal with the problem,a novel adaptive tracking algorithm is proposed. The spatial-temporal constraints of the tracking region and non-tracking region in sequence are modeled through a conditional random field (CRF),the parameters of which are updated using online learning method according to the changes of scene. The pixels of all images can be labeled as target or background based on the CRF model. During tracking,the optimal label field and the confidence map are first achieved by resolving the CRF model. Then the similarity measure between the target model and the target candidates,combined with the confidence map,is fed to the mean shift algorithm for the target localization. A selective sampling update strategy is utilized to alleviate the model drift. The experimental results demonstrate the efficiencies of the proposed algorithm in several real sequence testings.

SnO2 nanorod arrays are prepared by hydrothermal synthesis in autoclave at glass substrate. The structures and morphologies of SnO2 samples are investigated by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The growth principle of SnO2 nanorod arrays is explained. Ethanol sensing properties of SnO2 at different reactive times in autoclave and different annealed temperatures are studied. The best test parameter is found,and ultraviolet (UV) light enhanced ethanol sensing properties of SnO2 are investigated at room temperature. The results show that SnO2 nanorod arrays prepared in autoclave 6 h and annealed at 500 °C exhibit the best gas sensing property at room temperature. The gas sensitivity and stability of the SnO2 are increased by 365 nm UV light. And response and recovery time are shorten to 5 s.

GaN ultraviolet (UV) photocathode is a type of photoemission material with negative electron affinity (NEA) surface.The photocathode has high quantum efficiency,low dark current,good stability and many other virtues,therefore it has become a new-type UV detection material in recent years.Using atoms absorption technique in ultra-high vacuum system,experiments of high-low temperature two-step preparation are made on p-type MOCVD expitaxial GaN.The two-step preparation includes four steps,which are high temperature cleaning,Cs/O activation,low temperature cleaning and Cs/O activation.The experimental results show that GaN photocathode with about 20% quantum efficiency is obtained after high temperature cleaning and Cs/O activation.Photoemission current is still observed after low temperature cleaning.After subsequent Cs/O activation the photocurrent of photocathode can be restored,but the value is only close to the level after high temperature activation.This indicates that GaN photocathode material only needs single-step activation to be prepared.The differences of two-step preparation effects between GaN and GaAs photocathode material are compared,and preparation mechanisms of GaN photocathode is also discussed.

Graphical growth was realized by the use of lithographic technology on the ITO glass substrate covered with zinc oxide (ZnO) thin film. Rectangular and circle ZnO arrays which had integrated structure and orderly arrangement were prepared on substrate by hydrothermal method. The ZnO nanocone arrays were secondarily grown based on graphical once growth. The maximum length was 10 μm. Its length was far longer than the length which was grown by once growth. And many needle-like micro-structures of nano scale were found on the tip of nanocone. The field emission performance of ZnO nanocone arrays which had been prepared by non-graphical,graphical once growth and graphical secondary growth were analyzed. A 12.7 cm (5 inch) size FED was fabricated by using the ZnO nanocone cathode array. And it can realize full-screen light emitting. The experimental results showed that the emission current density of ZnO nanocone by graphical secondary growth was the greatest. Its emission current density was 0.6 mA/cm2 and its turn-on field was 2.5 V/μm. The graphical growth of ZnO nanocone was a feasible method for improving field emission properties. The results provided an effective experimental method for preparing good field emission performance material.

In order to solve the reflection of the germanium surface,the square pillar subwavelength structures are analyzed and designed by model theory. The results show that filling factors that are bigger than 0.78 have a more important effect on transmittance when periods is smaller. Zero transmittance decreases so quickly with periods increasing while sum transmittance decreases so few with periods increasing when periods are bigger than 0.25λ. The relationships between transmittance and depth are cosine when the period is smaller while the relationships between transmittance and depth are pseudo cosine when period is bigger. Besides transmittance is high within wide incident angles when the period is smaller,when the period is bigger the subwavelength structures can be made narrowband filter.

GaN-based light-emitting diodes (LED) thin films were successfully transferred from the original Si(111) substrate to Si substrate via bonding,copper substrate and copper-chromium substrate via electroplating respectively,and then the vertical-structure LED were fabricated. The aging characteristic of those LED was investigated. The result indicated that the devices of copper substrate have the most stable photoelectric properties. These different performances were attributed to the different stress states and thermal conductivities,and it was possible that the main influencing factor of reliability of LED was the stress state of the device.

Based on the excimer laser cornea correction mathematical model and the clinical wave-front aberration data,the influence of treatment decentration on wave-front aberration in conventional laser refractive surgery is studied. The result reveals that treatment decentration may induce the distinct increase of coma. The induced coma is nearly proportional to the treatment decentration and the corrected refraction. But other Zernike coefficients except for coma from third- to fifth-order aberrations approximatively maintain constant with the increase of treatment decentration. The increase of higher-order aberrations after refractive surgery may be attributed to the treatment decentration,the effect of oblique incidence of laser spot and the effect of biological response of the cornea.

A method of controlling chaos in nondegenerate optical parametric oscillator (NOPO) is presented in this paper. The chaotic state of NOPO can be converted into periodic state by modulating the driving field and the reduced decay rate of the fundamental mode with a sinusoid wave. The numerical simulation results based on the Lyapunov exponent spectrum,phase portraits as well as time series show that there are different periodic states for the chaos of NOPO system corresponding to different modulating amplitude and modulating angular frequency only if the maximum Lyapunov exponent of the system is nonpositive.

Designing methods of null test computer generated hologram (CGH) for freeform surface optical element are researched. Bicubic non-uniform B-spline interpolation is used to fit a continuous phase function from scattered phase compensation data,which is calculated by universal ray tracing numerical method. Matrix representation of bicubic B-spline and monotonicity of CGH phase function are used to calculate the precise intersection lines of planes paralleling to x-y plane and the interpolated B-spline surface,and the positions of fringes of a phase-only CGH are solved with high accuracy. Finally a design example of null test CGH for freeform surface optical element is presented.

Plasma Pockels cell,which can use a thin crystal to perform the uniform electro-optical effect,is an ideal component as average-power optical switch with large aperture. With average power load,the thermal effect of the DKDP crystal is analyzed by use of finite element methods. With 5 J/10Hz laser irradiation,the depolarization loss on 3 mm thickness DKDP is 0.16％. A repetition rate plasma Pockels cell of 10 Hz with Φ20mm aperture has been fabricated. It is optimized with the limited space of repetition rate diode pumped laser. The specificationes of the plasma Pockels cell are static transition of 97.2％;switching efficiency of 99.8％,and the switch rising time of 11 ns.

A demodulation principle and system for the multi-channel multiplexed Fabry-Pérot fiber-optic accelerometers in parallel based on a Fizeau interferometer are proposed,and the Fabry-Pérot fiber-optic accelerometers are based on the principle that the acceleration can be sensed through changing the length of the Fabry-Pérot cavity by the inertial mass. The function of the relative output intensity from the Fizean interferometer with the Fabry-Pérot cavity length of the accelerometers and the wedge thickness of the Fizeau interferometer is established. Furthermore,a theoretical acceleration model for the multiplexed Fabry-Pérot fiber-optic accelerometers based on Fizeau interferometer is also established. On these bases,the demodulation and multiplexing principle of the multiplexed Fabry-Pérot fiber-optic accelerometers based on the Fizeau interferometer are numerically simulated and the multiplexing capacity is analyzed. The research results indicate that the numerical results are consistent with the theoretical analysis and the accelerometers are feasible.

By analyzing the basic principle of Solc filter,it was concluded that the filter can be tuned by varying optical path difference of uniaxial crystal. As nematic liquid crystal provided with electric-control birefringent effect,a tunable Solc filter using parallel nematic liquid crystal cell as electric-control birefringent phase element was put forward. One representative form of six-patch fan structure has been designed and fabricated. Experimental results revealed a good tuning ability of the device. A tuning range of 450-650 nm with spectral resolution of less than 93 nm and a 550-650 nm tuning range with spectral resolution of 20 nm were obtained. The Solc filter has the advantages of high transmission and few sidelobes,and can be applied in high transmission requiring cases.

Three red microcavity organic electroluminescent devices (MOLED) with different thicknesses were designed and fabricated,the device structure was as follows:Glass/DBR/ITO (thickness of 150,182,and 196 nm respectively) / NPB (82 nm) / DCM-Alq3 (71 nm) / Mg-Ag (70 nm). With the increase of ITO layer,the cavity length of microcavity devices increased accordingly,and the devices' resonant mode (light-emitting peak) changed from 604 nm to 640 nm and then to 656 nm,CIE color coordinate changed from (0.52,0.48) to (0.61,0.37) and then to (0.61,0.38),indicating that the color purity increased gradually. The optimal electroluminescent performance was observed in the sample with the ITO thickness of 150 nm,the emitting center wavelength was 604 nm,the maximum brightness reached 32008 cd/m2,and the maximum current efficiency was 3.15 cd / A. It shows that the ITO thickness of the microcavity light-emitting devices affects the microcavity OLED’s light-emitting properties a lot due to the micro-cavity effect.

A novel method of fabricating a convex microlens array with wide scope for collecting optical information and transferring it with high efficiently and excellent capabilities of withstanding external stress and temperature is presented. By lithography and ion-exchange,a hexagonal aperture planar microlens array is fabricated on a spherical glass substrate successfully under strict control of the crucial process such as coating titanium,photolithography and ion-exchange etc. There are 2052 microlens in the substrate and each one is with a length of side and an edge-to-edge interval of 0.173 mm and 0.200 mm,respectively. Measurement and test show that the ion-exchange depth is 0.198 mm,the fill factor of the array reaches 98%,and the array has significant characteristics including perfect imaging,fine optical uniformity,ion-exchanged rotation-ellipsoidal region with three-dimensional refractive index profile,intercept and numerical aperture varying from center to edge and well conforming optical performance at same radius.

In order to improve the sensitivity of accelerometer and meet the needs of high-precision measurement,it is very important to improve the sensitivity of optical sensing structure. A theoretical design of a novel grating-based accelerometer is proposed. The mathematical model is established and the optical properties of the structure are analyzed. The formula of the optical intensity is given,and the curve of the optical intensity variation is figured with Matlab. The main factors of the sensitivity are analyzed. Through changing the parameters of the structure,the sensitivity of the optical sensor is improved. An experimental demonstration experiment is built and the correctness of the theoretical analysis is verified.

A new cavity structure containing negative refractive index dielectric layer is introduced into microcarity organic light-emitting devices (MOLED). Based on the transfer matrix method,the reflectance spectrum,the relation between the reflectance and incident angles and the dependence of electric luminescence (EL) spectra on cavity thickness were analyzed and discussed. The results show that the new MOLED have broader reflection band and better angular property than that of ordinary MOLED,compared to the same structure MOLED containing positive refractive index dielectric layer. The cavity thickness has little effect on the EL spectrum. So the thickness of the MOLED can be very thin. The new structure is beneficial for improving the properties of the MOLED.

Considering two-mode entangled coherent light field,one mode of the field is poured into the cavity and interacts resonantly with a cascade three-level atom. The squeezing and antibunching effects of the light field outside of the cavity are investigated,and Cauchy-Schwartz inequality is discussed. The influences of the selective atomic measurement and the intensity of the coherent field which interacts with atom on squeezing and antibunching effects of the field outside of the cavity are also discussed. The results obtained by numerical calculations show that quantum properties of the field outside of the cavity can be strengthened through selective atomic measurement and selecting the intensity of the coherent field which interacts with atom.

The coherent optical control of exciton quantum states in semiconductor quantum dots (SQDs) is essential for quantum information and quantum computing. The decoherence physical mechanisms of quantum dots (QDs) can be acquired through analyzing the influence of Rabi oscillation,which provides the theoretic support on all-optical coherent control of multilevel excitonic system. Self-assembled InGaAs QDs is excited by the linear polarized pulse field,the exciton dynamics equations of a three-level V-type system with single pulse are deduced from the master equations of the populations and the Bloch vectors. Based on the exciton dynamics equations,the effect of initial conditions and pure dephasing on Rabi oscillation are discussed. The results show that the amplitude and frequency of Rabi oscillation on exciton can be manipulated by adjusting initial conditions and the polarization angle of excitation field,and the simple intensity dependent damping factor of pure dephasing can well describe the decoherence properties of the V-type three-level system,so that relevant calculation is simplified.

In order to avoid the difficulty of testing the reflectance of spherical mirror,two methods to establish the SURSI irradiance calibration are introduced. One is the method by using indirect parallel light and the other method is by using the direct diverging light. Detail descriptions of calibration processes of the two methods and a series of comparison and analysis of the calibration results are given. The relative deviation of calibration results between two methods is 1.0%. The absolute uncertainty budget of the 250-400 nm spectral irradiance calibration using the parallel light method is ±2.8%,and the relative uncertainty budget is ±2.0%. The budgets using the diverging light method are ±2.4% and ±1.4%,respectively. The relative deviation value is less than that of any one of the two relative calibration uncertainties. The analysis result shows that the direct diverging light method to calibrate the space ultraviolet remote sensing instrument (SURSI) is more effective to reduce the radiometric calibration uncertainty compared with the indirect parallel light method.

A new beam combining and aperture filling technique using conjugate Dammann grating is introduced to direct all the energy of a mutually coherent laser array to the far-field main lobe in theor. The design scheme of beam combination for one-and two-dimensional coherent laser arrays is demonstrated. An experiment using an idealized simulated laser array with a mask is performed,which verifies the proposed concept. Experimental results show that such a beam combination scheme is efficient technique for the high-brightness and high-power laser systems. This technique is based on the far-field diffraction theory. The relation between grating plane and array plane is Fourier transformation. The aperture size and power density of the combined beam can be conveniently changed. It is very significant for the development of compact,light weight,and high-quality laser systems.

The ground states(S0)of the 2-methyl-4,5-di(α-furyl)oxazole (compound A),2-phenyl-4,5-di(α-furyl)oxazole (compound B),2-α-furyl-4,5-di(α-furyl)oxazole (compound C) and 2-α-furan ethenyl-4,5-di(α-furyl)oxazole (compound D) were optimized with density functional theory (DFT) at B3LYP/6-31+G level,respectively. Single-excitation configuration interaction (CIS) method was used to calculate and optimize the excited states(S1)of the four compounds. The relation among the frontier molecular orbital energy,the absorption spectra,the emission spectra and the structure of the four compounds were discussed. The results show that the theoretically calculated spectrum data well agrees with the experimental value,and especially,the calculated maximum emission spectrum wavelength is more close to the experimental data when the pure density functional theory (DFT-OLYP) method is used. In addition,the frontier molecular orbital energy gap analysis indicates that the larger the conjugation system is the more distinct the red shift of absorption spectrum is.

White-light spectral interferometer for measuring physical thickness and reflection phase of thin film is designed. A novel algorithm is also presented to compensate the phase retrieval error in traditional signal processing method. Exact reflection phase is retrieved via a multiple variable optimization algorithm,and the result of linear fit is used as the initial guess. Numerical simulation is performed to demonstrate theoretical availability and high precision of the algorithm. A group of single layer TiO2 thin films are measured and processed with this method,and the retrieved physical thickness results fit the results by photometry very well. The system and algorithm presented provide a new way for fast measurement of thin film thickness.

Ion-doped mesoporous TiO2 thin films with regular mesoporous structure ware successfully prepared through the sol-gel method and spin-coating. The Zn2+,Fe3+-doped TiO2 thin films exhibit mesoporous structure with pore size of 7-9 nm,and the Y3+-doped TiO2 thin films exhibit mesoporous structure with larger pore size of 10.9 nm,which characterized by small angle X-ray diffraction patterns and TEM photographs. Optical properties were studied through the thin film transmission spectra of three kind of metal-doped mesoporous TiO2 thin films,and the refractive index of the films were fitted by Swanepoel envelope method. It can be found that after doping with Fe3+,optical absorption edge of mesoporous TiO2 thin-films was obviously broadened;and Y3+ dopants protects the collapse of mesoporous structure from the excessive growth of TiO2 nanocrystalline,offering a help to obtain mesoporous thin-films with large pore size.

TiNx/Ag/TiNx multilayer films are deposited on glass slides by magnetron sputtering. The crystalline structure of multilayer films and chemical composition of TiNx thin film are characterized by X-ray diffraction and X-ray photoelectron spectroscopy (XPS). US-VIS absorption spectrophotometer is used to investigate the effect of nitrogen flow rate and each layer of multilayer films on visible transparency. The results indicate that the TiNx thin films are amorphous and Ag thin film is crystalline. The TiNx thin film,on the surface of which exists a lot of Ti-O bonds,bears responsibility for improving the far-infrared reflectivity of multilayer film. The transmittance of films,firstly increases and then decreases with the increasing of thickness of Ag thin film,and it is improved with the increase of nitrogen flow rate . When the nitrogen flow rate is 55 cm3/s,and the conformation of multilayer film is TiNx(16 nm)/Ag(16 nm)/TiNx(32 nm),the visible transmittance of multilayer film reaches up to 85% at the wavelength of 550nm,the far-infrared reflectance is up to 92% and the emissivity is 0.0925,which presents very good optical properties of low-E glass.

In order to reveal the effect of gloss on color-difference evaluation,the printed samples are prepared by ink jet printer on matte,semi-gloss,gloss three papers with different gloss levels at the 5 basic international commission on illumination (CIE) color centers. About 1100 pairs of samples are carried out by 23 observers with normal color vision based on the psychophysical method of pass-fail. The calculated CIELAB color difference shows that the color discrimination thresholds have no obvious difference for different gloss.The STRESS is proposed to test the four classical color-difference formulae,CIELAB,CMC,CIE94,CIEDE2000 and CAM02 series CAM02-LCD,CAM02-SCD,CAM02-UCS. For the original color difference formulae,except the CIELAB,the others have no obvious discrepancy. For the optimized kL values,the higher gloss the smaller kL,which indicates that the lightness difference is more noticeable for the higher gloss printed samples for evaluating color difference.

The manufacture of high-line-density X-ray transmission self-focusing varied line-space (VLS) gratings for X-ray spectroscopy by using electron beam lithography is reported. Firstly,the VLS gratings are automatically optimized and generated by the macro program. Then using the electron beam lithography and micro-electroplating technology,the VLS gratings are fabricated on polyimide membrane substrate. The 2000 lp/mm X-ray transmission VLS gratings are successfully obtained. It can be seen that the line space of the gratings are all desired. The calibration results of diffraction efficiency of the VLS gratings indicate that the VLS gratings have promising abilities to significantly improve the diffraction intensity and spectrum resolution in the central wavelength.