In order to meet the requirements of freeform surface shape measurement, an optimization method of deformable mirror shape design for freeform surface partial compensation interferometry is proposed to overcome the problem that multi-parametric optimization is easy to fall into local optimization and can not effectively constrain the deformation range of deformable mirror. The optical simulation system is established based on the principle of ray tracing, and the deformable mirror shape is characterized by Zernike polynomials. The deformation range of deformable mirror is constrained by calculating the vector height of the surface, and an optimal solution model with constraint conditions is constructed with the wavefront as the optimization objective. Based on the nodal aberration theory, the optimization variables are selected, and the global optimal solution is found by combining the simulated annealing algorithm. In order to measure a typical freeform surface, a catadioptric partial compensator based on deformable mirror is designed. The simulation results show that the method can reduce the peak valley value of residual wavefront from 32.20λ to 6.55λ, and the maximum residual wavefront slope from 0.53(λ·pixel-1) to 0.11(λ·pixel-1), which meets the requirements of partial compensation detection.

In order to realize the optimal luminance-equalized color conversion for multi-primary color display, a convex hull method to compute the display gamut volume is proposed, and a color conversion algorithm by nonlinear optimization of a luminance equalization merit function is proposed. First, the color coordinates are uniformly sampled in XYZ color space, and the color coordinates located in the device gamut volume are judged by the convex hull algorithm. Then, the luminance-equalized drive values corresponding to the color coordinates in device gamut volume are calculated to establish the mapping from XYZ color space to device color space. Color gamut computing and luminance-equalized color conversion are realized with a six-primary LED display. The results show that the proposed algorithm can achieve color conversion with a luminance variation coefficient of 0.1685 averagely.

Curved Computer-Generated Hologram (CCGH) can increase the Field of View (FOV) in holographic display. However, the huge data processing is still a challenge for real-time display. A fast calculation method for CCGH based on double-step Fresnel Diffraction (DSF) is proposed. The method includes two steps: the first step is to use DSF to generate a planar computer-generated hologram, and the second step is to compensate the planar computer-generated hologram into a curved computer-generated hologram according to the law of light diffraction propagation. Numerical simulation results show that compared with the direct calculation using the point source method, the calculation time is greatly shortened, and the quality of the reconstructed image meets the viewing needs of the human eye. The optical experiment results are consistent with the numerical simulation results. It is expected that the proposed method can be widely used in real-time curved holographic display in the future.

The working stability of the optical fiber-coupled Terahertz time-domain spectral system is mainly limited to the interpolation stability during the delay scanning of the optical delay line. A new high-stability optical delay line scanning device is designed to solve this problem. Optical simulation tolerance analysis of the new optical delay line and the traditional optical delay line shows that when its internal the pyramide mirror and the collimator have the same degree of tilt and eccentricity conditions, the coupling efficiency fluctuation of the new optical delay line is much smaller than that of the traditional optical delay line. The experimental results of terahertz time-domain waveforms comparison show that the peak fluctuation of the terahertz time-domain signal obtained by the new optical delay line designed by this scheme is only 1/4 of that of the traditional optical delay line. A feasible scheme is provided to improve the stability of fiber-coupled terahertz time-domain spectroscopy system.

Aiming at the accuracy, real-time and synchronicity requirements of Terahertz human security inspection instrument for data acquisition, the problems of amplitude nonuniform error, clock jitter and sampling trigger jitter of the acquisition system are analyzed, and the acquisition system structure of active Terahertz human security inspection instrument is proposed. In order to determine the allowable range of clock jitter in the acquisition system, a high-precision programmable time-delay clock tree network structure is designed to realize the output of seven-channel sampling clock, sampling trigger signal and synchronous clock with homology, low jitter and consistent phase. Finally, the system test scheme is introduced. Experimental results show that under the same test conditions, the clock tree mechanism of terahertz human security inspection acquisition system within -40~ 40MHZ band, I and Q signals were collected good orthogonality, waveform distortion and the amplitude are equal, the second harmonic signal spectrum is below -40dB. Compared with the traditional system, the harmonic suppression reduced by more than 10dB, can be used in the field of terahertz human security inspection.

In the Terahertz wall detection system, a detection method based on Terahertz wave is presented to solving the existing problem that due to the crosstalk of reflected signals of adjacent steel bars when multiple steel bars are side by side. The problem of overlapping influence measurement is caused by Terahertz beam illuminating two adjacent steel bars, which is solved by installing a focus beam with adjustable lens group in front of the Terahertz source. What is more, the improved algorithm is used to detect the side-by-side steel bars buried at different depth. The results reveal that the measurement error is less than 0.5mm when the cement depth is 40mm and the distance between two side-by-side steel bars is 25mm. The measurement error is also less than 1mm when the adjacent steel bars have a depth difference of 40mm.

An all-fiber femtosecond pulses amplification system was researched. A nonlinear amplifying loop mirror resonator delivering broad-spectrum seed pulses was employed, and the fiber chirped pulse amplification technique was adopted to supress the accumulation of nonlinearity during the power amplification process; Besides, combining the fiber fusion spliced technique of the double-clad fiber and large-mode field photonic crystal fiber, the main amplification system generated high-quality picosecond pulses with 1030nm central wavelength and 16.9W average power. After the spatial grating pairs’dispersion compensation, the pulses duration had been compressed to 324fs with energy of 12.2μJ, corresponding to a peak power of about 26.4MW. All-fiber structure was realized by using special polarization maintaining fiber fusion technology instead of free-space coupling, the optical path structure and stability of environment was further optimized. All the ways mentioned above are expected to improve the process of high-energy fiber laser industrialization and adaptability in the complex environment.

In order to meet the need of the spaceborne CO2 lidar for the frequency stability of the seed light source, a set of frequency-stabilized laser was built based on the free-space body absorption cell combined with the frequency modulation spectroscopy technology.A set of frequency stabilization lasers were built through simulation and optimization of system design parameters. Studied the multi-beam interference noise was introduced by the volume absorption cell. By adjusting the modulation frequency to an integer multiple of the free spectral range of the interference fringe of the absorption cell, the influence of interference noise was suppressed, and the peak-to-peak value of the laser frequency jitter was about 150kHz, and the long-term frequency stability is lower than 1×10-11 at 10000s,which meets the application requirements of spaceborne lidar.

Laser cladding technology is used to prepare Fe-based cladding layer on the surface of helical gear steel. The metallographic structure and microhardness of the cladding layer are analyzed by optical microscope and microhardness tester, and use abrasion machine to perform friction experiment on the cladding layer and the substrate. The results show that when the laser power is 750W, the powder feeding rate is 20g/min, the scanning speed is 10mm/s, and the defocus is 16.4mm, there is a clear white band at the interface between the iron-based cladding layer and the substrate, and the laser cladding effect is better. The hardness value of the cladding layer ranges from 845.3HV to 955.6HV, which is about 2 times the hardness of the matrix (419.7HV), the friction and wear performance of the cladding layer has been improved, the microstructure of the cladding layer is uniform and fine ferrite and pearlite, and the mechanical properties are better than the matrix Material.

A non-standard ellipsoid condenser design method based on the binomial expansion is proposed in order to improve the effective concentration efficiency of the condenser for the solar simulator. This method controls surface shape of the condenser by changing the quadratic coefficient of the expansion. The non-standard ellipsoid condenser enhances the ability to converge defocused light energy, and improves the effective energy utilization by making the energy distribution more compact on the second focal plane. An ellipsoid condenser is used to analysis and simulate to display the actual lighting by Monte Carlo ray tracing method. Simulation results show that concentration efficiency of the non-standard ellipsoid condenser is about 10% higher than standard ellipsoid at the effective area.

Aiming at the nonlinear frequency tuning issue of the internal modulation tunable laser source(TLS) in conventional Optical Frequency Domain Reflectometry(OFDR) systems and its further influence on the diminish of signal to noise ratio, an OFDR system based on optical IQ modulation is proposed. The principles of the optical IQ modulation and the basic OFDR sensing system is analyzed. The frequency sweeping laser source based on optical IQ modulation and the OFDR temperature variation positioning system are established. The system utilizes optical IQ modulator to modulate frequency stabilized laser for linear frequency sweeping laser generation. The linear frequency sweeping laser is injected into the OFDR system to locate temperature variation on fiber under test(FUT). The experiment results demonstrate that the OFDR system based on optical IQ modulator is capable of sensing and locating the temperature variation on FUT with high accuracy. A temperature variation localization sensing with 0.0606m sensing error is achieved on an 1000m length fiber. The research shows that the optical-IQ-modulation based OFDR system can realize a temperature variation positioning function at a middle or long distance with high accuracy.

Aiming at the problem that the existing 3-PZT phase-shifter is difficult to drive the large-aperture reference mirror for phase-shifting interferometry, a high-precision piezoelectric ceramic driving power supply for the measured element phase-shifting interferometry system is designed. The power supply that adopts error-amplification structure outputs the control signal through the proportion difference and optocoupler isolation according to the deviation between the input signal and the output sampling, and then controls the conduction state of MOSFET, adjusts the charge and discharge current, and controls the output of the DC voltage generated by the voltage doubling rectifier circuit, so as to realize the stable control of the output voltage of the driving power supply. Experiments show that the high-precision piezoelectric ceramic driving power supply has the ability that outputs continuously adjustable voltage in the range of -600~600V, and has ripple less than 20mV, high linearity and accuracy, good stability. It can realize the retractable and accurate phase-shifting of piezoelectric ceramics, and can meet the requirements of the surface measurement of the large-aperture measured mirror by the measured element phase-shifting interferometry system.

An ultraviolet light transmission experimental system is designed with a 275nm light emitting diode as the light source and photodiode as the detector. Firstly, the transmission characteristics of the system under two transmission modes, line-of-sight and non-line-of-sight, at different distances are tested. Then the transmission characteristics under different light source elevation angles and detector elevation angles are tested. Finally, the experimental results with the theoretical results are compared. The results show that in the non-line-of-sight mode, the received power is inversely proportional to the elevation angle of the light source, and the farther the distance, the smaller the effect of the elevation angle of the light source on the transmission characteristics of the system. The elevation angle of the detector at 30°~60° has little effect on the transmission characteristics of the system. The results of this research provide a certain reference for the design of ultraviolet communication system.

The threshold of random laser light is closely related to the scattering intensity in the system. After the high refractive index titanium dioxide (TiO2) nanoparticles and the dye-doped polymer dispersed liquid crystal (DDPDLC) were uniformly mixed, due to the strong scattering effect between the liquid crystal droplets and the TiO2 nanoparticles, DDPPLC's random laser had a lower lasing threshold, which varied with the doping concentration of TiO2 nanoparticles. On the basis of optimizing the doping of TiO2 nanoparticles, the emission threshold of DDPDLC was as low as 270μJ/cm2, and the linewidth was reduced to 0.08nm. Finally, the temperature experiments proved that the scattering of PDLC structure was the main working mechanism for the generation of random lasers. After TiO2 doping, the DDPDLC samples still ensured a good tunability.

This article aims to clarify the coloration mechanism of butterfly wings, and apply it on textiles dyeing and printing, to solve the problem of high water consumption and heavy pollution in textile industry. Two butterflies living in temperate zones were studied, which are Limenitidini and Sasakia charonda. SEM was used to observe the microstructure of two areas of each butterfly. It is found that there is non-smooth surface on wing scales, such as spinal veins, cross-rib, etc. Ocean USB2000 UV-vis-NIR micro spectrophotometers was used to perform multi-angle spectral tests on four areas, and it was found that only the purple part of Sasakia charonda showed the phenomenon of wave crest shifting with angle, which is characteristic of structural color. Then ethanol was used instead of air as mesenchyme of purple area, and the color changed, which verified the photonic crystal structural color mechanism. At last, a photonic crystal model was established based on the microstructure of the purple part of Sasakia charonda, and the band gap was calculated using the plane wave expansion method. Then the relationship between color and band gaps was analyzed.

Aiming at the problem of low detection accuracy and detection recall rate of traditional remote sensing image aircraft target detection algorithm in complex background, a remote sensing image aircraft target detection algorithm based on YOLOv4-tiny in deep learning is proposed. First, according to the network structure of YOLOv3 and YOLOv4, the network structure of YOLOv4-tiny is improved, and the CSP feature extraction network in the original algorithm is strengthened to increase its feature extraction ability. Then, use the Mish activation function to replace the original activation function Leaky ReLU to obtain better generalization. Finally, a spatial pyramid pooling module is added to alleviate the sensitivity of the network to the target scale. The experimental results show that: in the conventional high-quality, over-exposed tarmac, boarding gate interference and foggy remote sensing image test, the improved algorithm has excellent detection results, and the final statistical detection accuracy is 98.49%. Compared with the original algorithm, an increase of 1.79%, a recall rate of 97.19%, an increase of 23.2%, and a speed of 8.77ms. The detection effect has been significantly improved and can meet real-time requirements.

In order to make the fused remote sensing image have excellent contrast while highlighting the texture features, a double restriction model to fuse the remote sensing image in the non subsampling shearlet transform domain is designed. Firstly, the multispectral image is analyzed by IHS model, and divided into intensity, hue and saturation components. Then, with the help of NSST, the low and high frequency coefficients of I component and panchromatic image are analyzed. Finally, through the information entropy and mean value model, the image rich information and brightness richness are calculated, and the low-frequency fusion coefficient is calculated. Using the convolution operation of image and direction matrix, the texture features of image are calculated. By calculating the standard deviation of image, the contrast information of image is obtained. Using the texture and contrast information of image, the double restriction model is constructed, and the high-frequency fusion coefficient is calculated with it, and then the fusion image is obtained. The experimental results show that the fusion performance of this algorithm is better than the existing algorithm, and the fusion image texture is more prominent, the contrast is better, and the information richness is higher.

In order to advance the denoising performance for Gaussian noise, an image denoising method based on differentiable shrinkage function and adaptive threshold is proposed. As per the fact that the wavelet coefficients of Gaussian noise obey Gaussian distribution with small amplitude, a threshold adaptive to the signal and noise intensity is designed, so as to accurately distinguish the noisy coefficients from the image coefficients. And in view of the fact that the wavelet coefficients of natural image have the characteristics of smoothness and continuity, a differentiable shrinkage function is proposed, which is to be integrated with the designed adaptive threshold for quantizing the noisy wavelet coefficient, so as to effectively remove the noise coefficients, preserve and restore the image coefficients. Experiments confirm the fact that compared with the existing wavelet based denoising methods proposed recently, the proposed method removes noise more effectively, and is more capable of preserving and restoring the details and texture structures.

In order to understand the mechanical properties of rock in part of Karakoram (China Section), the dynamic evolution laws of rock sample displacement field, fracture initiation and propagation were studied by using digital image correlation technology under three-point bending and uniaxial compression. Through the quantitative and qualitative analysis, it is concluded that the crack evolution and path are different due to different rock types. The crack of three-point bending rock sample occurs at the side of tensile stress, and the uniaxial compression specimen is at the corner. Local crushing leads to failure. By comparing the crack evolution, the cracks of phyllite and gneiss extend longitudinally along the maximum stress, while the cracks of mica schist are damaged under the influence of bedding and stress, the cracks extend zigzag. The experimental results can improve the understanding of rock failure mechanism in this area, and provide data accumulation and reference for disaster prevention and mitigation and engineering facilities construction.

Aiming at the problem that the most of image information hiding techniques need prior information and the difficulty of training, one information hiding method for images based on complex wavelet transform and adaptive pixels clustering is proposed. A new unsupervised population based optimization algorithm is utilized by the proposed method to cluster the pixels of secret image adaptively, then the support vector machine is adopted to select the optimal wavlet sub band of dual-tree complex wavelet transform of the carrier image, in order to maintain the imperceptibility of hidden information, the method treats the optimal wavlet sub band as carrier for hidden information. Experimental results show that the method realizes strong imperceptibility, and it not only has strong ability in resisting intrusions of steganalysis models, but also does not need any prior knowledge of the original carrier image and secret information during the information hiding process. It is a bind information hiding method.

Automatic microcell injection can overcome the shortcomings of long manual injection and easy fatigue, in order to solve the problem of cell and pinpoint location in automatic intracytoplasmic sperm injection. Based on the method of combining YOLOv3 neural network and level set, the egg cell and the injection needle are divided, and then the needle tip of the injection needle is located. The comparative experiment proved that the method can solve the problem that the traditional level set is difficult to segment cells and injection needles, and completely segment the deformed cells during microinjection as well as locate the needle tip in the cells, and the error is smaller than other algorithms.