Thermal distortion parameters are proposed to evaluate the intensity of thermal blooming effect of repetitively long pulse laser. A numerical simulation model of thermal blooming effect of repetitively long pulse laser is established, and experiments are carried out. By comparing the simulation results with the experimental results, we find that the experimental results are agree well with the simulation results in terms of spot shape and size, which verifies the reliability of the mathematical-physical model of repetitively long pulse laser and the simulation algorithm. On this basis, the quantitative relationships between the spot expansion and the thermal distortion parameters caused by the repetitively long pulse thermal blooming effect, named scaling laws of thermal blooming effect of repetitively long pulse laser, are obtained by a large number of numerical simulations under different atmosphere parameters and launching system parameters.

In order to eliminate the influence of the location and number of spectral channels on the ranging accuracy of the oxygen absorption attenuation passive ranging technology, we discuss the basic principle of passive ranging technology based on oxygen absorption attenuation, and analyze the spectral line characteristics of oxygen A and B absorption bands. For spectral channels in the shoulder of the absorption band, the Monte Carlo method is used to analyze the influence of the position and the number of spectral channels and degree of fitting polynomial on the accuracy of non-absorption baseline fitting according to the sum of error squares and the correlation between the non-absorption baseline and the ideal baseline. For the spectral channels in the absorption band, the influence of the absorption rates in different spectral channels on the measurement range and the ranging accuracy is analyzed. Considering the real-time and precision of the system comprehensively, we find that each shoulder of the A absorption band has one spectral channel, and single shoulder of the B absorption band has two spectral channels. The location of spectral channels all should be chosen at the end of each shoulder near the absorption band. The spectral channels in the absorption band can be flexibly selected according to the requirements on the measurement rang and ranging accuracy. Therefore, if the complete spectral curve in the ranging waveband cannot be collected in one-time exposition, the monocular multispectral passive ranging system, using the fewer spectral channels and the simplest linear fitting method, will not only ensure the ranging accuracy of the system, but also reduce the time period of filter replacement and software calculation, and thus enhance the real-time performance of data acquisition and calculation.

The cumulative fatigue damage of deformable mirrors (DMs) is generated due to the action of the circular mechanical drive of the actuators in the process of adaptive wavefront correction. The wavefront correction process of the DM has been simulated by the least squares method and the influence function of the DM, and the corresponding stress distribution of the DM in the wavefront correction process has also been analyzed by the finite element method. Additionally, the fatigue life of the DM has further been calculated with the Miner cumulative fatigue damage theory. On this basis, the influences of the structural parameters of the DM on the influence function and the fatigue life of the DM have been discussed. The results show that the coupling coefficient of the DM is minimal and the fatigue life is the longest when the poles are distributed in the triangular arrangement for the given distorted wavefront and the equal number of poles of the DM. However, the coupling coefficient of the DM is maximal and the fatigue life is the shortest when the poles are distributed in the square arrangement. Furthermore, the coupling coefficient of the DM decreases with the increasing pole spacing, resulting in the increasing fatigue life of the DM. Meanwhile, the coupling coefficient and the fatigue life of the DM decrease with the increasing pole radius and the decreasing pole length when the pole spacing is fixed. On the whole, the influence of the pole spacing on the fatigue life of the DM is more significant than that of the pole radius and length. Furthermore, for the given pole spacing, the number of the poles varies with pole distribution manners and the fatigue life of the DM decreases with the increasing number of poles.

The skylight polarization distribution pattern in Yellow Sea is studied. The distribution properties of polarization pattern of the sunlight and the moonlight above the sea are analyzed, and the effects of clouds are also investigated. The polarization distribution patterns of the sunlight and the moonlight are simulated based on the Rayleigh scattering theory, and then the polarization patterns of the sunlight and the moonlight in Yellow Sea are measured with an image full-sky polarization pattern measurement system. The polarization measured results of the sunlight and the moonlight are compared with the simulated results. The differences and similarities of neutral points and the direction of the meridian in the polarization pattern are analyzed emphatically. The results reveal that the measured directions of the meridian of sunlight and moonlight are mostly in accord with the theoretical results. The measured neutral points of sunlight have the same rules as the theoretical patterns, but the measured neutral points of moonlight are apparently different from the theoretical results. In the civil evening twilight, the skylight polarization pattern is affected by both the moonlight and the sunlight. Owing to the influence of the cloud on the polarization direction angle and the polarization degree, the measurement instrument cannot identify the part of the polarization pattern at present.

The proportion of multiple scattering in the lidar echo determines the attenuation coefficient KLidar, which affects the inversion of the water optical property parameters. At present, the Walker-McLean model and the multiple forward scattering-single backscattering model are both expressed with the formula form to describe multiple scattering components in the theory of ocean lidar. Based on the underwater laser transmission mechanism, the equivalence of multiple scattering factors in these two models is analyzed, and the items involving multiple scattering are compared to discuss the similarities and differences of these inversion models for water optical property parameters. Based on the comparison of scattering phase functions of the two models, it is found that the results obtained based on the Walker-McLean model are more consistent with measured results. Multiple forward scattering-single backscattering model is suitable for medium with strong forward scattering. The inversion value of water optical properties is lower than the actual value when the laser just enters into water, and it gets higher value as the multiple scattering times increase.

On the basis of constructing the lookup-table of the backscattering efficiency factors of three wavelengths (355,532,1064 nm) and the extinction efficiency factors of two wavelengths (355 nm and 532 nm), the aerosol backscattering coefficients of three wavelengths and the extinction coefficients of two wavelengths (3β and 2α) are calculated. The inversion of spectrum distribution parameters of unimodal log-normal aerosol is simulated by nonlinear fitting. Results show that the spectrum distribution parameters of unimodal log-normal aerosol can be successfully inversed by this method. The effects of the different initial values on inversion results are small. The complex refractive index plays an important role in the inversion of the aerosol spectrum distribution. When the real and imaginary parts of the complex refractive index have the uncertainty of +1 and -1 step length respectively, the relative errors of the number concentration of particles, geometrical standard deviation and median radius are 20.32%, 33.50% and 24.72% respectively. The real part of the complex refractive index brings greater error than imaginary part. The study provides a theoretical foundation for the study of inversing vertical profile spectrum distribution of aerosol with multi-wavelength lidar.

A terahertz quantum well photodetector (THz-QWP) is designed and the many-body effect is investigated in this device. By characterizing and analyzing the photo-current spectrum of this device, it is found that the many-body effect changes the peak response frequency and causes the phenomenon of two response peaks, and thus it is confirmed that the many-body effect can deepen the depth of the effective well potential and simultaneously increase the energy spacing between the first excited state and the ground state. Therefore, it is important for the THz-QWP design to take the many-body effect into account.

A sub-wavelength transmission grating is designed and fabricated, which is utilized for the realization of diode laser array spectral beam combining. Based on the strictly coupled wave theory, the grating duty ratio, ridge height and period are designed, the effect of different structural parameters on grating diffraction efficiency is simulated, and thus the optimization of the grating diffraction efficiency is realized. The theoretical calculations show that, for a 940 nm laser, the -1 order diffraction efficiency of the optimized grating can reach 92%. The experimental results show that the output power is 46.2 W and the beam quality is 3.9 mm·mrad after the laser array spectral beam combining.

The changes of temperature and strain will cause the center wavelength drift of fiber Bragg grating (FBG) reflection wave. The FBG can be combined with giant magnetostrictive material (GMM) to measure the current, but the cross sensitivity of temperature and strain seriously affects the accuracy of the current measurement. The neural network has strong nonlinear mapping ability, which can adaptively find out the internal law of the sensor to compensate the temperature effectively. For the problem of neural network is easy to fall into the local minimum, the genetic algorithm is applied to optimize weights and thresholds of neural network and find the optimal solution of weights and thresholds quickly and accurately. In order to improve the reliability of the network prediction, the K fold cross validation method is used to solve the problem of small sample size. The experimental results show that the mean square error of the optimized neural network for current prediction is 0.0038, which improves the measurement accuracy of FBG current sensor.

Two anti-interference structures of sensing fibers with variable pitch parts in fiber optic current sensors are proposed. One is fundamental structure, where the variable pitch part is bunched with the sensor fiber and the reflector is placed in the midpoint of the variable pitch part. The other is "8"-shape anti-interference structure, where the variable pitch part is wound into an "8" shape. The anti-interference principles of the two structures are analyzed. The differences of sensor readings are tested when the current conductor is at different points inside and outside the sensor fiber coil. The experimental results show that the external 1000 A level current disturbance can be resisted away from 0.5 m for both structures. However, the former only is applied to the applications where the relative positions of the current conductor and the sensor fiber coil are unchanged, while the latter can be applied to the many applications where the relative positions of the current conductor and the sensor fiber coil are not fixed. The anti-interference performances of both structures under different applications are practicable.

A mathematical model is established by the Mie scattering theory and the pulse multipath effect to predict the maximum communication rate based on the horizontal atmospheric visibility. With the method of Monte Carlo simulation, we obtain the scattering functions of the aerosol scattering particles at 800 nm and 1550 nm, respectively, and the pulse broadening curves of the two wavebands in the visibilities of 2-25 km. The influence of the initial pulse width, the pulse position modulation (PPM) element and the horizontal visibility on the communication rate is analyzed. Results show that the communication effect is better in 1550 nm band and the maximum communication rate improves with the increasing visibility. Under the good visibility, the small initial pulse width and PPM element can maximize the communication rate.

Based on the temperature tunable principle of π phase-shifted fiber Bragg gratings, a thermo-electric cooler and a refrigeration wafer are used to control the temperature of a π phase-shifted fiber Bragg grating, and then change its central wavelength. Its central wavelength has a bathochromic shift with temperature rising. As the temperature rises from 0 ℃ to 95 ℃, the central wavelength changes from 1548.921 nm to 1550.664 nm with a total change of 1.743 nm. The sensitivity is approximately 18.35 pm/℃. In order to verify the temperature tuning properties of π phase-shifted fiber Bragg gratings, we design a C-band ring-cavity fiber laser by using high reflectivity fiber Bragg grating(FBG) with matched reflectance spectrum. We use narrow-band filtering characteristics of π phase-shifted FBG to realize narrow linewidth fiber laser output,and control the temperature to realize continuous tuning of output laser wavelength.

A novel fiber sensor for measuring strain and refractive index based on fiber Mach-Zehnder interference (MZI) principle and core-offset splicing technology was designed. The sensor was composed of a single mode fiber at both ends with core-offset fibers. Measurement of external refractive index and strain was realized based on sensitive characteristic of optical fiber cladding mode and core mode to strain and refractive index. The tested results indicate that wavelength of near infrared transmission spectrum shifts to shorter wavelength with a sensitivity about -7.00 pm/με at the dips 1585 nm under an axial strain 0-500 με; the wavelength shifts to shorter wavelength side with a sensitivity about -55.223 nm/RIU at the dips 1570 nm under 1.331-1.398 RIU refractive index, where RIU is refractive index unit. The fitting has a good linearity. This fiber sensor can also be applied to other sensing fields and have good prospects.

In order to solve the problem of astigmatism which affects the clarity in virtual system, a type of reflection surface design is put forward for astigmatism correction in the full field, and the design algorithm of the anastigmatic reflection surface based on differential equations is presented. The designed anastigmatic surface can correct astigmatism at each field of view effectively and decrease the size of dispersion spot. An astigmatic surface is applied in the off-axis virtual display system with the field of view of 60°×40°, and the radius of dispersion spot at each field of view is less than that of the Airy disk. The design results of the anastigmatic reflection surface are compared with the results designed by a spherical and a toroidal surface with the same parameters. It is found that the root mean square radius of dispersion spot and the absolute value of astigmatism designed by anastigmatic reflection surface are less than 20% of the result designed by a spherical reflective surface at the full field, and they are less than 20% of the result designed by a toroidal reflective surface at the margin field.

With the development of information networking, the application of quick response (QR) codes is more and more diverse. The recognition and application of traditional single QR code cannot meet the current demands. Therefore, a correction algorithm for multi-target QR codes is proposed. The image is binarized and the code symbolic characteristics are used to locate the QR codes. The QR codes are segmented based on those characteristics and the connected components labeling algorithm. Then, contour tracing is used to obtain the boundaries of the QR codes detection pattern. Three vertices on the detection pattern are obtained by using the geometric relationship. The fourth vertex is obtained by the relationship between the probe point and the other vertices. Finally, the inverse perspective transformation is used to correct the code shape. The proposed algorithm is implemented by C++ programming language, and the corrected QR codes are tested by Zbar. Experimental results show that the proposed algorithm can carry out the correction of multi-target QR codes quickly with high recognition rate, and can overcome the influence of different illumination and background interference, showing good robustness.

In view of the problems that the target contour of the fused image is fuzzy and its details are not highlighted by the use of traditional fusion algorithms, an infrared and visible image fusion algorithm based on the shearlet frame and neighborhood structure features is proposed. The shearlet transform is used to decompose the source images to get the subbands coefficients of high frequency and low frequency with the same size as the original images. Then, in order to prevent the edge of the fusion image from blurring after fusion, a fusion rule based on geometrical distance combined with energy distance is adopted in low frequency subband coefficients. Moreover, a fusion strategy based on gray difference and gradient distance weighting is used to fuse high frequency subband coefficients for keeping the details of the images better. Finally, the fusion image is obtained by shearlet inverse transformation. Results show that the proposed algorithm can effectively extract the target infrared information and keep the visible image information. On the basis of retaining the image profile information,the proposed algorithm can highlight the target information, and improve the image fusion effect effectively.

The road detection method based on color image exists problems under the extreme lighting conditions and changing road surface types, and the computing resource in moving platform is limited. So, based on the 9-layer convolutional neural network, a fast road detection algorithm is proposed to mix the color image and the disparity images. A new preprocessing method is applied in the data input layer, which can transform the disparity images to disparity gradient maps so as to enhance the representation of roads and reduce the demand for network depth. Two proposed networks are proposed including a double-path convolutional neural network which is used to analyze the characteristics of the convolutional neural network, and a single-path convolutional neural network which is applied to detect the road rapidly. The performance of the proposed algorithm is experimentally compared and analyzed on the KITTI road detection dataset which is divided into a common database and a difficult database artificially. The result demonstrates that, compared with the convolutional neural network method based on color images, the MaxF1 measures on the common database and difficult database improve by 1.61% and 11.58%, respectively, and the detection speed can be 26 frame/s. The proposed algorithm can overcome the impact of the lighting, shadow and the changing road surface effectively.

The mixed manifold spectral clustering adaptive segmentation method is proposed, while the laser point cloud is regarded as a linear and nonlinear mixed manifold in three-dimensional Euclidean space. The mixture probabilistic model is constituted by M principal component analyzers, which are constructed by the mixtures of probabilistic principal component analysis method, and the adjacency matrix of point cloud is obtained. In the spectrum space, the geometrical characteristics of point cloud segmentation are embedded in the dimension, and the multi-dimensional vector, which describes the characteristics of point cloud classification, is obtained by N-cut method. The between-within proportion algorithm is adopted to segment point cloud adaptively. Experimental results show that the proposed algorithm can obtain segmentation results that converge to the geometric features with the probability larger than 80% in wide range of preset parameters. Moreover, it performs stable with Gaussian noises of 0 mean, 0.01 standard deviation and compound noise of 0.25 times the total points. The proposed method shows good noise resistance.It is applied to point cloud of satellite model acquired by slice laser three-dimensional imaging and achieves good segmentation results.

Imaging spectropolarimeter can concurrently obtain the spatial information, spectral characteristics and polarization information of the target, it is a well-recognized technique and widely used in scientific applications, such as astrophysics, detection of atmospheric composition, biomedicine and other areas. The polarization information is generally acquired with the tradeoff of the decrease of the spectral imaging spatial resolution in imaging spectropolarimeters. An interferometric imaging spectropolarimeter using dual-channel lateral shearing beam splitter is proposed to avoid the decrease of spatial resolution. A dual-rectangle lateral shearing beam splitter is used in imaging spectropolarimeter, which makes it a dual-channel imaging spectropolarimeter. The two channels are used for high spatial resolution interferometric imaging and polarization spectral imaging based on micro-polarization array, respectively. The principle of the dual-rectangle lateral shearing beam splitter and the Fourier transform polarization spectral imaging based on micro-polarization array modularization are analyzed. The spectrum recovery method and extraction mode of polarization information are discussed. High spatial resolution spectral images and polarization images of a scene in the visible region are acquired by the experimental apparatus, which proves that the proposed imaging spectropolarimeter can concurrently be used for polarization imaging measurement and high spatial resolution spectral imaging measurement.

A wavefront aberration model with respect to substrate deformation error of membrane diffractive lens is built by means of diffractive ray tracing and wavefront reconstruction method. Two typical cases of the substrate deformation errors, the edge wrinkle surface and the spherical surface with center outward structure, are demonstrated. Meanwhile, the influence of the deformation errors on related image quality is evaluated and the principal aberration type caused by the deformation errors is discussed. The relationship between wavefront root-mean-square aberration, surface peak-to-valley value and Strehl ratio (SR) is investigated. This work would be helpful in assembling membrane diffractive lens and compensating aberration in a real diffractive telescope system.

The detection and identification of the ship target on the sea surface is significant for the monitoring and the target strike. The weak ship target with less texture information is affected by the sea surface shadow and noise interference, which results in the poor detection results with common algorithms. The weak ship target detection algorithm on sea surface is proposed based on the channel separation and minus extend contrast sensitivity function. Firstly, the multi-resolution image scale pyramid of the pixel intensity channel and the noise-edge channel is constructed. Secondly, the minus extend contrast sensitivity function under different scale space is established, and the weight of each position is modulated. Finally, based on the weighted spatial scale coefficient, the two channels' saliency maps are obtained. The weak ship target detection of noisy image is realized by channel differential processing. The experimental results show that compared with the other five algorithms, the proposed algorithm has high detection precision (97.30%), recall (84.71%) and F-Score (94.49%), and has strong anti-noise ability which is suitable to the weak ship target detection of noisy optical remote sensing image on sea surface.

Simultaneous phase-shifting interferometry obtains multiple phase-shifting interferograms simultaneously to realize phase-shifting interferometry of the dynamic wavefront. In order to ensure the measurement accuracy, it is necessary to perform accurate position registration of the phase-shifting interferograms before implementation of the phase shifting algorithm. A position registration method based on the speed up robust features (SURF) algorithm and the random sample consensus (RANSAC) algorithm is proposed. Through the registration of background image with certain characteristics, the transform relation between corresponding images is obtained, which is used for the phase-shifting interferogram to realize position registration of the simultaneous phase-shifting interferograms. The simulation results show that the method is effective on the translation and rotation transforms in the case of non-uniform light intensity. The method can also obtain transform matrix by registration to achieve phase recovery under the white Gaussian noise. The method is applied to measure the standard plane with a four-step simultaneous phase-shifting micro-interferometer, and the peak-to-valley value and root mean square value are 23.2520 nm and 2.3149 nm, respectively.

Aiming at the problem of high magnitude target simulation in the lab, a weak-light single star simulator (WLSSS) consisting of light source, adjustable diaphragm, integrating sphere, photoelectric detector and collimator is developed to measure the magnitude detecting ability of detecting cameras and star sensors. The relationship between the readings of photoelectric detector, the spectral radiance in the outlet of integrating sphere and tunable obscuration ratio is deduced. Combining the magnitude definition formula and the image illuminance equation formula, the operation principle of weak-light single star simulator is introduced, and the calibration challenge of high magnitude target is solved. The magnitude simulation range and precision of WLSSS are theoretically analyzed, and results show that the highest simulating magnitude is 19.5 Mv, and the precision is 11.6%. When the simulation magnitude is lower than 15 Mv, its precision is better than 8%. Experiment results show that in the lab, the maximum relative error between simulated magnitudes and KLL-04 wide-range illuminator tested magnitudes is 7.09%. The relative error of measured magnitude detecting ability between laboratory and astro-observation detecting cameras is 1.9% in 6.5 Mv, and 2.6% in 15.2 Mv. The designed WLSSS can effectively simulate high magnitude targets.

Chirped pulse spectral interferometer (CPSI) is an ultrafast single-shot diagnostic instrument, the large chirped pulses reference, pulse detection and accurate measurement of its spectral of electric field are critical factors to realize ultra-high time-resolution and large range of testing simultaneously. Based on the spectral interference between transform limit femtosecond pulse and chirped pulse, a linear optical measurement method for spectral phase measurement of large chirp pulse is proposed by theoretical analysis and numerical calculation. It is called asymmetric spectral interference method. Investigations show that when employing the asymmetric spectral interference method to measure the spectral phase of chirped pulses in CPSI, translation error of the time delays and relative smaller chirp of femtosecond pulse will produce a first order phase error. Consequently, the time-domain signal measured by CPSI will generate a time translation, but the relative time evolution of the measured signal is not affected.

When the target is at high temperature and far from the imaging system, its image on the detector array occupies dozens of pixels and the output grayscale is easy to saturate. As a result, typical process methods for point-source target and extended-source target are not applicable any more. To overcome these problems, a measurement method is proposed measure high-temperature infrared small targets, and the effectiveness of the proposed method has been validated by experiments in the outfield. First of all, the radiometric calibration formula of measurement system in high temperature range is built, and the influence of the collimator transmittance on the calibration model is corrected. Then, according to the fact that the target energy diffuses dozens of pixels but the total energy that reaches the detector array remains unchanged, a measurement method is proposed to measure the characteristics of high-temperature infrared small targets. Finally, a Φ600 mm infrared radiation characteristic measurement system is employed to measure the radiation of high-temperature infrared small target in the outfield. Experimental results indicate that, in consideration of the atmospheric transmittance and path radiance, the proposed method can achieve high-accuracy measurement for remote high-temperature infrared small targets, and the effectiveness of the proposed method has been verified.

In order to realize accurate and fast measurement of the inner raceway surface accuracy of a slide block, a method of tilt measurement based on laser triangulation displacement sensor is proposed. The method is reasoned and verified, and the experiment is carried out by means of high precision round bar. According to the characteristics of measuring system and shape of inner raceway of the slider, the corresponding model is established. Relevant algorithm is used to calculate the radius of inner raceway of the slider, and the error source in the measurement process is calibrated and compensated. Then, on the basis of inner raceway contour algorithm, parallelism and position of the axis of slider internal raceway relative to the base plane are calculated. Finally, verification test of this scheme is introduced and the results are analyzed. The test results show that the measurement accuracy of the standard round bar is 3.75 μm and the standard deviation is less than 2 μm. The test results meet the requirements of measurement accuracy of 5 μm. Moreover, the measurement method does not have pose requirements for reference piece and part to be tested, so it has certain generalization performance.

Exposure result of scanning beam interference lithography (SBIL) system is closely related to the movement property of the stage. The stage adopts coarse-fine dual stage mechanism to fabricate large-area plane grating with nanometer accuracy. The fine stage is the key point of the movement accuracy of the stage. According to the principle of SBIL, the relationship between interference fringe period measurement accuracy and exposure contrast is deduced. For the period measurement method of interference fringe by moving beam-splitter, the positioning accuracy index of the fine positioning stage is analyzed by considering period measurement accuracy requirements. A controller design method is proposed to realize the positioning accuracies of the degrees of freedom in x, y, θz directions. And the experiment is conducted in the fine positioning stage system. The results show that the positioning accuracy of x, y, θz can achieved ±1.51 nm, ±5.46 nm and ±0.02 μrad, respectively, which can satisfy the SBIL exposure requirements and the interference fringe period measurement accuracy requirements.

Aiming at the problem of repeated calibration in the traditional mobile screen deflectometry, a deflectometry measurement method of single-camera monitoring is proposed based on the principle of the phase measurement deflectometry. The two positions of a LCD screen were monitored by an auxiliary camera, and the position of the LCD screen relative to the main camera was determined by the PnP method and the coordinate system transformation. The incident light was determined by the absolute phase tracking of the homonymy phase points at two positions of the LCD screen for the same pixel. Accordingly, the normal line and gradient information were determined and the mirror surface was reconstructed accurately through the radial basis function interpolation. The two cameras with different fields of view were calibrated by the mirror calibration method. The calibration was implemented only once without the repetitive error. The results of the simulation and experiments verify the feasibility of the proposed method and show the method has a relatively high detection accuracy.

We design an elliptical crossing waveguide with high efficiency based on multimode interference (MMI), adding a mode matcher and adjusting the self-focusing position to reduce its transmission loss. The COMSOL simulation shows that the transmittance of the waveguide reaches 96.5% and the crosstalk loss is less than 2×10-5 at 1550 nm, while the transmittance is 91.2% for traditional elliptical crossing waveguide. The imaging law of elliptical MMI is analyzed theoretically and verified in simulation. The results show that the new elliptical structure not only exhibits high efficiency at 1550 nm, but also has very low loss (less than 0.2 dB) and crosstalk (less than -42 dB) for the whole communication band from 1500 nm to 1600 nm. This cross-light waveguide is small-sized, simple-structured, and is formed by only one step etching with the grating couplers on a silicon-on-insulator (SOI) platform. It has simple preparation process and is conducive to cost savings and mass production. So it will be widely used in integrated optics in the future.

Aiming at the problem of inconvenient placement of a target in the measuring plane and the difficulty of making a large-scale target in wide-area monocular plane measurement system, a method of calibrating with small-size plane targets laid on a parallel plane is proposed. A parallel plane is selected as a calibration plane, a single small-size plane target is placed reasonably in a plurality of positions on the calibration plane for shooting, and a large-scale plane target is constructed by combining the photos and the nonlinear optimization method is used to complete the optimization of the internal and external parameters of the camera. Combining with the parallel constraint and the distance parameter, the homography matrix between the measuring plane and the image plane is obtained and then the wide-area plane measurement is realized. The precision model of plane measurement is established, and the distribution of precision in the measuring area and the factors influencing measurement precision such as the internal parameters, the installation angle and height of the camera are analyzed theoretically and experimentally. The experimental results show that the proposed method can effectively guarantee the overall measurement precision. In the calibration in a trapezoidal visual field with an upper line of 920 mm, a lower line of 1360 mm and height of 920 mm, the measurement error is lower than 0.6% in the measuring plane away from the calibration plane 200 mm. The distribution of errors in the measuring area is consistent with that of the precision model. This method is fully applicable to the wide-area plane measurement.

In order to improve the recognition rate in single-band images of ship targets with complex background, we propose a new fusion recognition method based on convolutional neural networks (CNN). This method extracts the ship target features of images in three wave bands, which are visible light, medium-wave infrared and long-wave infrared images. The model is divided into three steps. Firstly, a 6-layer CNN model is designed to extract the image features of three bands simultaneously. Secondly, a feature selection method based on mutual information is used for sorting the concatenated features according to the importance, and then the feature vectors of fixed dimension can be chosen depending on the indicator of image clarity evaluation. The dimension-reduced feature vector is regarded as the basis of target recognition. Finally, a 2-layer fully connected networks and an output layer are designed for training and regression. We build a triple-band ship target dataset for our experimental verification, which contains 6 categories of targets and more than 5000 images. The experimental results show that the recognition rate of the proposed method can reach 84.5%, which is improved significantly compared to that of the single-band recognition method.

A flexible dual-stopband terahertz metamaterial filter with polarization insensitivity is proposed and designed. CST 2015 simulation software is used to simulate the structure of the designed metamaterial filter. To further study transmission characteristics of the metamaterial filter, we simulate the electric field intensities and surface current distributions of the metamaterial filter, respectively. To verify the validity of simulation results, we prepare a metamaterial filter sample by using the micro-manufacturing technology, and measure the transmission performance of the filter by using the terahertz time-domain spectroscopy (THz-TDS) system. The results show that the filter has two stopbands with 3 dB bandwidth of 15 GHz and 10 GHz at resonance points when the resonance frequencies are 0.131 THz and 0.182 THz, respectively. The transmission coefficientS21 at the two resonance points can reach -43.56 dB and -48.76 dB, and the filter shows good stopband characteristics. The measured results accord with the simulated ones.

Full-chip multi-parameter optimization is an important development direction of resolution enhancement techniques in optical lithography. A source mask projector optimization (SMPO) method based on particle swarm optimization (PSO) algorithm is proposed. The pixels are used to represent source. The discrete cosine transform basis functions are used to represent the mask. The coefficients of Zernike polynomials are used to represent the projector. The source, the mask and the projector are encoded into particles. The pattern error is adopted as the evaluation function and the particles are updated iteratively to realize the SMPO. This method is simulated and verified by using the complex mask pattern with cross gate design in nominal condition and process condition. Results show that the pattern errors are reduced by 94.2% and 93.8%, respectively, and the quality of lithography imaging is effectively improved. Compared with SMPO method based on genetic algorithm, the proposed method has a faster convergence rate. Besides, the proposed method has the advantages of high degree of optimized freedom and enhanced manufacturability of the optimized mask pattern.

The transmission matrix of the magneto-optical (MO) nonlinear fiber Sagnac structure is deduced, which can be used to analyze the influences of fiber birefringence, MO effect, nonlinear phase shift, the polarization controller state and the total loss of the fiber loop on the transmittance of Sagnac. The MO modulation of Sagnac structure and functions of nonlinear optically-controlled-optical switch are experimentally investigated. The MO modulation degree can reach 17.05 dB under the applied magnetic field of 0.0177 T, which is in good agreement with the theoretical analysis. When the peak power of the clock pump control signal is 28.2 dBm, the extinction ratio of optically-controlled-optical switch can reach 25.8 dB. The extinction ratio of the switch can increase 0.7 dB by further applying the magnetic field. To some extent, the magnetic field response of the optically-controlled-optical Sagnac structure may be equally analyzed with the help of polarization control state.

To obtain light emitting diode (LED)-packaged substrate with high luminous efficiency and high thermal conductivity, the direct aluminum (Al) plating technology is used to prepare aluminum/aluminum oxide (Al2O3) composite ceramic substrate whose surface is also polished by chemical-mechanical method. The optical and thermal performance of the LED light source packaged by this composite substrate are simulated by using the optical simulation software Tracepro and the thermal simulation software ANSYS. This LED light source is also compared with the traditional alumina ceramic substrate package LED light source. Finally, the prepared aluminum/alumina ceramic substrate is packaged into an on-board chip-mounted (COB) type LED light source for testing. Both results of simulation and experimental tests show that the aluminum/alumina ceramic substrate prepared by direct aluminum process has faster heat transfer rate, better thermal conductivity and it is more suitable for high power LED light source packaging. LED packaged by Al/Al2O3 ceramic substrate has bigger luminous flux and higher luminous efficiency, compared with the light source packaged by traditional Al2O3 ceramic substrate.

As an outstanding quality multi-functional crystal, potassium tantalate niobate (KTN) crystal is notable for its quadratic electro-optical effect. An electronically controlled birefringence effect based on the crystal is found during the experiment of electro-optical modulation. To illustrate this kind of performance that one electronically controlled beam is separated into two beams of orthogonal polarization light, the principle of quadratic electro-optical effect and the Fresnel equation are used to construct the mathematic model of beam separation deflection. The reason for the phenomenon is elucidated theoretically, and the function relationship between voltage, incident angle and deflection angle of extraordinary light is given. In the experiments, the electronically controlled birefringence phenomenon of KTN crystal is further measured and the corresponding theory is verified. The experimental results show that KTN crystal has obvious electronically controlled birefringence effect and large deflection angle of extraordinary in the case of 532 nm laser oblique incident.

Fibonacci zone plate (FiZP), with properties of bi-foci in focal plane and self-reconstruction, can simultaneously trap particles positioned in two different planes and move particles freely in the focal plane. The structure and axial strength of FiZP are analyzed. The experimental platform is established by combination of liquid crystal spatial light modulator, inverted optical microscope and optical elements, and used to capture particles in three dimensions. Experiments show that the FiZP beam has three-dimensional optical acquisition characteristics, and can be used to build three-dimensional optical tweezers and achieve complex capture function.

Hyperspectral inversion of soil water content is a current hot research topic. Hengshan County of Shaanxi Provice, which has diverse soil types, is taken as study area. Soil samples are collected in the field and their spectra are tested indoor using ASD Field Spec FR ground object spectrometer. Moreover, the soil water content is calculated by weighing method and the spectral features of the soil samples with different water contents are analyzed. For the construction issue of factors in the spectral inversion of soil water content, and based on the study of inversion input factor generation method and the existing problems of first order differential (FD)-principal component analysis (PCA), wavelet packet transform (WPT)-FD-PCA, the method of constructing the inversion input factor of WPT-FD-HA-PCA based on harmonic analysis (HA) is proposed. On the basis of the three above-mentioned inversion input factors, three back propagation (BP) models of soil water content (FD-PCA-BP, WPT-FD-PCA-BP, WPT-FD-HA-PCA-BP) are constructed. Comparison between the measured values of soil water content and the inversion values of the three BP models shows that the inversion accuracy of WPT-FD-HA-PCA-BP model is the highest. The coefficient of determination (R2) and root mean square error between measured value and inversion value is 0.9599 and 1.667% respectively, and it performs better than the other two models. The results show that WPT and HA can effectively suppress the spectral noise and compress the signal, and to some extent, the inversion precision of soil water content is improved obviously.

In order to extend the receiving range of scattering angles and improve the measurement accuracy and resolution of submicron particles by laser particle size analyzers, a simple-structure method based on an annular sample cell is proposed. In theory, it can receive the scattering light of 0°~180° continuously and seamlessly and possesses the advantage of low measurement limit. Based on the measurement method with annular sample cells, a new-type measurement device of laser particle sizes is constructed and the standard particles of 50, 100, 200, 400 nm and their mixtures are measured, whose results are compared with those of the traditional sample cells. The results show that the method based on the annular sample cells can distinguish the mixed standard particles with a median volume diameter ratio of 1∶2. This scheme has signatures of low measurement limit, high measurement accuracy, high resolution and high reliability for submicron particles.

Based on the scattering potential theory and the first-order Born approximation condition of weak scattering, the influences of the center position offsets and the boundary condition variations of the sub-wavelength spherical particles on the spectral density distribution of the scattered evanescent waves are studied. The near-field components of the scattering light are expanded in the angular spectra, and the double integral expression of the complex amplitude of evanescent waves is obtained. The angular and radial parameters are integrated with the numerical integral method, and the related distribution characteristics between the spectral density of evanescent waves and the scattering parameters are obtained. The results show that the scattered evanescent waves contain the characteristic informations of the center positions and the boundary conditions of the scattered particles whose radii are within the range of the effective scattering radius. These informations disappear rapidly with the increase of propagation distance. The study results are conducive for the detection and structural inversion of tiny particles with complex spatial structures.

The electrophoretic mobility of a charged particle can be determined using the electrophoretic light scattering method. To accurately determine the particle's Zeta potential from the mobility requires the use of Henry function. An optimal expression for Henry function can be fitted by using the least squares algorithm. The thickness of the electric double layer in different concentrations and different types of electrolyte can be calculated using the Gouy-Chapman-Stern double layer model. An accurate value of ka is obtained, here k -1 is the thickness of the double layer and a is the particle radius. The value of ka can be used in the optimal expression to determine an accurate value of Henry function. The particle's Zeta potentials for four different concentrations are measured using this approach. The experimental results show that the optimal Henry function can be used to improve the calculation precision of particle's Zeta potential, and the relative error of the calculation results is less than 1.0%.

In order to use the near infrared spectroscopy to rapidly detect the concentrations of fat, protein and lactose in the milk, a preprocessing method of weight resetting for near infrared spectroscopy based on histogram normalization and fuzzy analytic hierarchy process is proposed. The principal component analysis is conducted for the spectrum of milk samples, the best principal component number in the spectral data is determined, and the scores and weights of the principal components are obtained. Filtering and purification and noise elimination of two-dimensional spectral matrix are realized by using the mathematical statistic idea of histogram normalization. The fuzzy analytic hierarchy process is used to reset the weight of the active principal component information, and the irrelevant interference information of principal component is filtered out, thereby, the spectrum is reconstructed. On this basis, partial least squares 1 (PLS1) regression models of fats, proteins and lactose are built after spectral data preprocessing, getting the correlation coefficient of fat is 0.980 and predicted root mean square error is 0.158×10-2 g·mL-1; the correlation coefficient of protein is 0.997 and predicted root mean square error is 0.050×10-2 g·mL-1; the correlation coefficient of lactose is 0.985 and predicted root mean square error is 0.152×10-2 g·mL-1. Through the model prediction results, we can see that this pretreatment method has better filtering and noise elimination effect than the conventional pretreatment method. It is feasible to pretreat the near infrared spectrum of milk by combining histogram normalization and fuzzy analytic hierarchy process.

A series of phosphors Ca12-x-yMxAl14O32F2∶yEu (M=Mg, Sr, Ba) are synthesized by the high temperature solid-state reaction, and their phases and fluorescence properties are tested by using X-ray powder diffractometer and fluorescent spectroscope. The composition and structure of Ca12Al14O32F2∶Eu3+ /Eu2+ can be adjusted by doping alkaline metal ions, and the luminescent properties of Ca12-x-yMxAl14O32F2∶yEu (M=Mg, Sr, Ba) are affected. The results show that doping Mg2+ in Ca12Al14O32F2∶Eu is not conducive to the reduction of Eu3+, but doping Sr2+ or Ba2+ is helpful for the reduction of Eu3+. Adjusting the concentration ratio of Eu3+ to Eu2+ by changing the doping concentration of alkaline earth metal ions, the intensity ratio of blue to red can be adjusted, and the color of the samples can be adjusted from blue to lavender, and to bluish green.

Near infrared spectrometer is an important optical analytical instrument and has important application. By setting the enter slit, middle slit and exist slit, a spectrometer with a single grating and dual channels based on quasi Littrow structure is built to detect near infrared spectrum with a high dynamic range and tunable resolution. The optical system is simulated by using Zemax software. Then, a near infrared spectrometer with wavelength from 600 nm to 1700 nm is set up, and the spectrometer is composed of the optical system, control and analysis system and detection system. The results show that the light passes through the plane grating twice with quasi Littrow angle, the spatial dispersion effect of exit light spot is eliminated and the size of exit light spot is reduced, and then the spectrum edge noise is effectively restrained and the intensity of stray light is reduced. The dynamic range of the spectrum is improved by using the self-developed high dynamic detect system that cooperates with optical system. After spectral calibrating and relative radiation calibrating, the narrow band laser source is detected by using the spectrometer. The highest spectral resolution of the spectrometer, that is full width at half maximum, is better than 0.05 nm, and the dynamic range of the recovery spectrum around the central wavelength with a tolerance of ±1 nm is better than 70 dB.

Optical films are prepared by using ion beam sputtering deposition. Basing on the spectroscopic ellipsometry measurement technique, the relationship between refractive index, film layer thickness, surface layer thickness and spot size is studied. The study results show that, with the increase of tested spot size on the sample surface, the refractive index of thin films decreases, while the film layer thickness and surface layer thickness increase. The spot effects of optical constants are verified by using the reflectance spectrophotometry and the profilometer, respectively. The study results show that the refractive index and the film layer thickness have weak transverse inhomogeneity, which can be weakened by the usage of large-size tested spots.

Projection decomposition of dual-energy computed tomography (CT) is a key step for dual-energy CT pre-reconstruction algorithm. The selection of iterative initial values has great influence on the convergence of the iteration when an iterative algorithm is use to solve the dual-energy projection integral equations. To solve the problem of selecting initial values in solving dual-energy projection integral equations, an optimized iterative algorithm is proposed. For calculating projection lookup tables of dual-energy basis materials and calibrating the system, a certain step length is set based on numerical ranges of high-energy and low-energy projection data. Thus the corresponding basis materials projection can be solved according to the order of the projection values. The convergent result of last time is taken as the initial value of next iteration. The results show that the proposed algorithm can effectively improve the convergence of the iteration and the efficiency of calibration of the duel-energy CT system, which proves the validity of the algorithm.

An ellipsoidal mono-capillary is designed and fabricated, and its performance is measured by both optical measurement and X-ray testing. The profile errors of the ellipsoidal mono-capillary is 15 μrad. The diameter of focusing spot is 40 μm and the launching angle of focusing spot is 1.75 mrad at energy of 9 keV. Based the developed ellipsoidal mono-capillary, a X-ray nano-imaging system is designed and constructed at the X-ray imaging beamline (BL13W1) in Shanghai synchrotron radiation facility (SSRF). The X-ray nano-imaging is achieved with utilization of the ellipsoidal mono-capillary, which indicates that the ellipsoidal mono-capillary can meet the requirement of X-ray nano-imaging.