Aiming at the technical shortcomings of the current handheld Raman micro spectrometer, such as narrow spectral range, poor spectral resolution and large volume, a design method of the spectroscopic system for the handheld Raman spectrometer with high-resolution and wide-spectrum was proposed. On the basis of the comprehensive consideration of installation, debugging and performance, the wedge-shape cylindrical mirror was innovatively used to eliminate the astigmatism, which not only ensured the signal strength, but also facilitated the mechanical installation. Under the premise of restricting the change of the outgoing beam aperture after grating diffraction at different wavelengths, the aberration characteristics of the crossed asymmetric Czerny Turner optical path structure was used to achieve the coma correction in the full spectrum range. Based on the ZEMAX software, the spectrometer structure was simulated and optimized, and the prototype was developed. The size of the prototype was 72mm×43mm×62mm. The performance was tested by the helium-neon lamp. The results showed that the resolution was better than 6cm-1 and the Raman spectral range was 150~4000cm-1, which verified the feasibility and rationality of the optical design of the micro-spectrometer system.

Sparse-aperture optical imaging system has affixed filling factor and certain transfer function characteristics. In order to improve the imaging performance of the system, and enhance its Intermediate Frequency (IF) information. the influence of the zoom structure on the imaging of the discrete sparse aperture system is analyzed, and the relationship between the focal length, filling factor and Modulation Transfer Function (MTF) is derived. A sparse-aperture telephoto imaging system with adjustable focal length in the range of 2857~4000mm is designed. The analysis of imaging characteristics shows that when the focal length of the system decreases, the filling factor increases, and the cut-off frequency of the MTF decreases, but the IF response of the MTF increases. Through image fusion, the clear IF fringe information of large filling factor is used to compensate the missing IF fringe information of small filling factor. The simulation imaging results show that the images obtained based on different filling factors can effectively improve the image quality of each frequency band of the whole image after fusion.

Combustion produces blackbody radiation and free radical radiation. In order to obtain the ultraviolet radiation information produced by flame combustion, an UV optical system based on the needs of flame spectral information detection was designed. The design increases the working bandwidth of the ultraviolet optical system and improves the conventional field of view of the telephoto optical system. The system combines the characteristics of wide spectrum, large relative aperture, relatively large field of view and high resolution, so as to obtain more accurate flame ultraviolet spectral information in a large range. Thus the basic flame information such as flame fuel composition can be obtained and improve the applicability of the UV system. The operating wavelength of the system ranges from 240nm to 390nm, and the operating bandwidth is wide. The F-number of the system is 2.5, the relative aperture is large, and the field Angle of view is 15°. The whole system is composed of ten lenses, the total length is less than 170mm, and the compact structure meets all the basic requirements of combustion detection. The image quality evaluation results show that the root mean square radius of the dispersion spots in each field of view of the system is less than 9μm, the maximum lateral color aberration of the system is less than one pixel in the full wavelength range, the value of the modulation transfer function (MTF) is better than 0.5 at the cut off frequency of 50 (lp·mm-1), and the system distortion is less than 0.5%.The design results show that the ultraviolet optical system has the advantages of excellent imaging performance, wide working bandwidth, small chromatic aberration, high resolution, and small distortion, etc. At the same time all the lenses of the system are the spherical lenses, which is convenient for processing and detection, and meets the design requirements.

In order to solve the drawbacks of the prism spectral imaging system, such as poor direct vision, low spectral linearity and large natural smile, a spectral imaging system based on double Amici prism is proposed. MATLAB software is used to realize the accurate calculation of the prism smile based on vector refraction law, which has been verified by simulation.On the basis of studying smile characteristics of double Amici prism, and as the dispersive element, a direct vision double Amici prism with smile eliminated is built. The wave band of the designed system is 400nm to 800nm, and the spectral resolution in the full waveband is higher than 7nm. At the central wavelength of 600nm, the angle between the chief ray of the center view refracted by double Amici prism and the optical axis is less than 0.31°. Moreover, the maximum value of the smile in the full waveband is less than 2.557μm, which can meet the requirements of direct vision and eliminating smile. It’s of general guiding significance to the design of prism spectral imaging system with smile eliminated.

Dynamic linear-motion-target generator is used to detect or calibrate performance indexes such as dynamic resolution or tracking bandwidth of electro-optical tracking and pointing system. A collimator is placed inside the dynamic target generator to simulate the infinite dynamic target, motion graphics are placed at the focal plane of thecollimatorand moves in a variable speed linear motion to simulatethe movement dynamics of the ground scene. Due to the characteristics of long focal length, large aperture and large field of view of the generator's collimator, the secondary spectrum of the collimator needs to be considered, based ontheory ofchromatic aberration eliminationthe secondary spectrum is corrected and other aberrations such as field curvature are balanced. An optical collimating systemwith focal length of 1 m and field of view angle of 5° is designed.The design results show that the MTF is better than 0.3@100lp/mm,the distortion is 0.03%, and axial chromatic aberrationis much less than the focal depth, which effectively corrects secondary spectrum. The on-axis and off-axis spatial resolution of the optical systemis detected by the resolution plate method, the detection results show thatspatial resolution of the collimatorreaches 152lp/mm, which meets the requirements of the system.

Phosphor-conversion light emitting diode (pc-LED), which is fabricated by covering infrared phosphor on the blue light diodes, is an ideal near-infrared (NIR) light source for its advantage of broadband, low power dissipation and easy integration in circuits. And discovering of high efficiency broadband near-infrared emission phosphor for light-emitting diodes is key to this technology. Herein, considering the high thermal stability of silicate matrix, and the similar ion radius of Sc3+ and Cr3+, a chromium doped silicate LiScSi2O6 (LiScSi2O6∶Cr3+) broadband NIR phosphor was prepared in this work by high temperature solid state, which emits a broadband NIR light, peaking at ~850nm, with a full width at half maximum (FWHM) of ~156nm, under the 450nm blue light excitation. The luminescence intensity remains 75.38% of that of at room temperature when the phosphor’s temperature is of 160℃. The luminescence mechanism of Cr3+ in LiScSi2O6 matrix and the model of thermal quenching were also discussed in this paper. A NIR pc-LED was fabricated by combined the phosphor with blue light LED chip, which shows a maximum output NIR power of 436.7mW @ 300mA, and a maximum electron-photon efficiency of 18.3% @ 1mA. This as-fabricated NIR pc-LED is also small in size light and in weight, and can be easily integrated in circuits, which made it have a good application prospect in the domain of night vision and information anti-counterfeiting.

CdSe QDs are important semiconductor nanomaterials. The water soluble cysteamine (CA)-CdSe QDs were one-step synthesized by using SeO2, cysteamine and CdCl2·2.5H2O as precursors. The influences of the refluxing time, pH of original solution, the precursor Se/Cd molar ratios, and reaction temperature on the luminescence properties of the obtained CdSe QDs have been systematically investigated.The structure and optical properties of CdSe QDs were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), UV-vis absorption spectra, and photoluminescence (PL) spectra. The results showed that QDs with CA modification for CdSe were of cubic crystal structure, particle size was about 2.0nm,and the emission spectra tunable from 560 to 589nm．

OAM beam splitting plays an important role in various domains. The spatial separation of different OAM components is achieved through the principle of optical coordinate transformation, in which the crosstalk between adjacent modes is also reduced. This study provides a new and more feasible scheme for the OAM beam splitting.

The odd-even function method and the N-rotation method are two commonly used methods in absolute flatness test. Both of them use the odd-even function decomposition algorithm in the process of recovering the surface shape, but they use different methods in solving the odd-odd function. The two absolute test methods are compared. The finite element analysis of the gravity deformation of flat is added to the simulation of the odd-even function method and the N-rotation method. The experiments of the odd-even function method and the N-rotation method are carried out on the flatness with a diameter of 100mm, and the surface shape recovery results are compared with the measurement results of the liquid surface method. The results show that the PV difference of surface shape restored by odd-even function method is 4.864nm, and that of surface shape restored by N-rotation method is 1.853nm. The results show that the accuracy of the N-rotation method is better than the odd-even function method when there is gravity. The effect of rotation angle error on the odd-even function method and N-rotation method is analyzed by simulation. The results show that the N-rotation method is stronger than the odd-even function method in resisting rotation angle error.

In the traditional focimeter measurement, due to the change of the curvature radius of the rear surface of the lens to be measured, the rear vertex of the lens and the diaphragm surface cannot be completely coincident, resulting in the situation that the power measurement error increases with the increase of the lens power. Aiming at the insurmountable measurement error in traditional measurement, a method of extracting different features from lens images with different powers is proposed, and the feature data sets of lenses with different powers are obtained. k-Clustering algorithm (KNN algorithm) for classification. Select single focus lenses -20 ~+20m-1 with a refractive index of 1.551 every 1m-1, and -15~+8m-1 with a refractive index of 1.56 and 1.60 every 0.5m-1 for lens image acquisition. The experimental results show that the classification Precision, Recall rate and F1 score of this method are all 100%, the three models can correctly identify all the corresponding test lenses and overcome this measurement error.

The rapid detection of particle size distribution of suspended particles in water can be realized by static light scattering method based on CMOS detector. However, the measurement range and accuracy of particle size based on forward light scattering method were difficult to improve, which was limited by the working characteristics of the CMOS detector and the size of the screen. Therefore, a multi CMOS measurement technology for particle forward light scattering was proposed, focusing on the splicing measurement method of dual CMOS scattering signals, and a CMOS detector ring-splitting method to eliminate background interference was designed to achieve accurate measurement of particle size in a wide particle size range. The results show that the upper limit of particle size measurement based on CMOS detector is increased to 1000μm, and the relative error of D50 measurement of 1000μm and 500μm standard samples is 0.7% and 0.1% respectively, and the measurement accuracy of large particle size particle size is high; The method of double CMOS detection increases the particle size measurement limit of single CMOS from 5μm to 2μm. the relative error of D50 of 5μm and 2μm standard samples decreased from 15.0% and 51.1% of single CMOS to 1.4% and 2.6% of double CMOS respectively.

Aiming at the requirements of localization, high performance and flexibility and portability of terahertz time-domain spectrometers, the principle of sequential equivalent sampling of weak terahertz pulse signals is analyzed, and a high-speed direct data acquisition system for terahertz photoconductive detection is designed. A direct-acquisition terahertz time-domain spectroscopy fast scanning system composed of femtosecond pulsed lasers, motorized optical delay lines, terahertz photoconductive antennas, direct data acquisition systems, three-axis displacement platforms, semiconductor refrigeration thermostats and PC computers. Finally, the system is tested and analyzed. The experimental results show that, under the same no-load test conditions, the system has a 9dB increase in the frequency domain dynamic range of the signal compared to the traditional SR830 lock-in amplifier system, and a 0.4THz increase in the effective spectrum width. After 512 times of time domain averaging, the system signal spectrum is the dynamic range exceeds 72dB and the effective spectral width is up to 3.5THz.

Aiming at the application requirements of monochromatic X-ray source in the field of medical detection, an optimized design scheme of tunable X-ray fluorescence monochromator is proposed. Firstly, the penetration depth of X-ray photons in human skin, bones and fats under different X-ray energy bands were analysised, and the optimal target angle, X-ray generation efficiency and radiation characteristics were calculated by using the Monte Carlo N Particle Transport Code (MCNP), and the metal anode target material was optimized too. On this basis, the single-energy X-ray conversion efficiency of the secondary copper target under different anode voltages (kV) was calculated by establishing the target structure, and the proportion of the Kα characteristic spectrum was also calculated. These relevant works could provide a basis for the optimization and application of the medical X-ray fluorescence monochromator.

Single-lens sky-screen is commonly used as indoor ballistic range velocity measurement device with linear array light source constitutes an isosceles triangle detection screen. The detection sensitivity directly affects the velocity measuring accuracy of sky-screen. The construction and measurement principle of detection screen are introduced, the sensitivity calculation model is set up, the calculation formula of luminous flux variation caused by the projectile shielding light source when projectile passing through detection screen is induced based on the edge effect of the optical lens and the principle of illumination attenuation with distance; The sensitivity distribution within the detection screen is obtained and verified by experimentation, normalized luminous flux variation produced by projectile passing through the optical axis as reference value. The conclusions provide guidance for the use and design of the velocity measurement system of the sky-screen with light source.

The research of image reconstruction algorithm under sparse angle is a key problem in the application of Emission Spectral Tomography in field distribution measurement. Algebraic Reconstruction Technique algorithm, Simultaneous Iterative Reconstruction Technique algorithm and Simultaneous Algebraic Reconstruction Technique algorithm are widely used iterative image reconstruction algorithms. Taking candle flame as reconstruction objects, the image quality evaluation indexes such as Mean Square Error, Peak Signal Noise Ratio, structural similarity and image Average Gradient are used to analyze and evaluate the image reconstruction effects of different algorithms, and a multi index optimization algorithm fusion technology is developed to make full use of the restoration and reconstruction advantages of the three algorithms to realize the partition reconstruction of flame three-dimensional temperature field, and the reconstruction temperature error is within 5%. The experimental results show that the developed algorithm fusion technology is suitable for the high-quality reconstruction of flame three-dimensional temperature field.

In order to solve the problems of image structure distortion and visual blur caused by insufficient utilization of hierarchical features between residual blocks, an image super-resolution reconstruction algorithm combining attention and residual aggregation is proposed. The network obtains multi-scale features through the shallow feature aggregation module and inputs them to the residual aggregation network, and adopts the progressive fusion strategy to aggregate the features of each residual block from both local and global aspects, so as to make full use of the level features of residual block. To further enhance the feature representation, a dual attention mechanism is used to focus on the interdependencies between features from space and channel, respectively. The experimental results show that, compared with SRCNN, FSRCNN and other methods, the reconstructed images have clearer structure and richer details.

In the process of colorization of NIR images, there are large modal differences between NIR images and visible images in poor images domain styles, which lead to color texture mismatch in the colorization results. The CycleGAN network is improved, a concatenated module called the Dilated Cascade Block is designed by taking advantage of the cascade structure and the Dilated convolution block. This module adopts the encode and decode cascade structure to replace the one-way connection structure in the original model residual network. A Dilated Convolution module is introduced into the coding-decoding cascade layer to further extract feature information of NIR images of different scales by utilizing the advantage of cavity convolution without losing texture details of the images. Finally, NIR of colorful images are obtained by decoding the NIR gray images. The algorithm uses the Dilated cascade method to solve the texture mismatch problem in the generation network. The perceptive loss function is used to improve the slow convergence of discriminant networks. Validation and analysis are carried out on NIR~~VIS dataset. Experimental results show that the proposed method can improve the structure and color texture of the original object better, and effectively improve the visualization effect of NIR images.

Aiming at the problem that Faster R-CNN is prone to miss detection of small targets in multi-scale target detection, an improved multi-scale target detection algorithm is proposed. Firstly, the low-level features used for small target detection are fused with high-level features used for large target detection. Secondly, an online hard example mining algorithm is applied to maintain a hard case sample classification pool for accelerating the iterative convergence of the neural network model, which could solve the problems includes uneven training samples and low training efficiency. Finally, the size of the detected target is calculated and counted for controlling the size of the anchor box and improving the generalization ability of the model. The experimental results show that compared with Faster R-CNN, the mean average precision (mAP) is improved by 8.61 and 5.47 percentage points respectively.

When airborne infrared detection system detects targets in the near-earth background, the ground will disturb the weak and small targets seriously, which leads to detection performance reduction of traditional detection methods for weak and small targets. In view of this problem, the generative adversarial networks are utilized to propose a weak and small target detection method of airborne infrared detection system in the near-earth background. The generative adversarial networks are constructed based on deep auto-encoder, and the inception mechanism is introduced to extract multiple scaled features of vision information, the residual block is also introduced to mitigate the vanishing gradient issue. In the adversarial training of the neural networks, the loss function of the generator consists of the moving loss and the adversarial loss, which improves the training effect of the generator. In the end, the experiments are carried on the public unmanned drone airborne infrared detection datasets, and the results show that the proposed method can detect the infrared weak and small targets in the near-earth background successfully, at the same time, the average precision and speed of the detection method are better than the compared methods.