In order to improve the calculation accuracy of slant visibility, a method based on Fernald-PSO is proposed to determine the aerosol lidar ratio. Firstly, the equation of aerosol lidar ratio and aerosol extinction coefficient boundary value is constructed under the condition that atmospheric extinction coefficients are equal at the bottom and the top of the uniform layer of the atmosphere. The second equation is constructed under the condition that aerosol optical depth derived from the lidar signal is equal to that obtained in AERONET. Finally, Fernald-PSO is used to solve equations, and slant visibility is obtained using the inverted aerosol extinction coefficient. The proposed method is verified by lidar and AERONET data, and the effects of aerosol lidar ratio on the slant visibility are analyzed. The results show that for the same signal, the larger difference between the assumed and calculated values of aerosol lidar ratio, the greater relative errors’ absolute value of aerosol extinction coefficient and slant visibility. The maximal errors are 18.93% and 19.90%, respectively.

A hydrogen sulfide gas sensor based on Cu/Graphene composite membrane coated waist-enlarged tapered Photonic Crystal Fiber (PCF) is proposed and fabricated. The Mach-Zehnder Interferometer (MZI) is formed by fusion splicing a section of PCF which is sandwiched between two Single-Mode Fibers (SMF), and the air holes of PCF in the splicing regions are fully collapsed and formed two waist-enlarged tapers. The outside surface of PCF is coated with a layer of nano-Cu-deposited graphene by using a dip-coating technique. Cu-deposited graphene-coated PCF is to make the sensor produce high sensitivity. With the increasing concentration of hydrogen sulfide, the output wavelengths appear blue shift. In addition, a high hydrogen sulfide gas sensitivity of 8.5 pm/ppm, the limit of detection of 3.85 ppm and good linear relationship and selectivity are obtained within a measurement range of 0~80 ppm for H2S gas. The response and recovery time of the sensor are 92 s and 119 s, respectively. The experimental results show that the sensor has the advantages of low cost, high sensitivity and simple structure, especially suitable for low concentration and high sensitivity detection of hydrogen sulfide gas.

Stimulated Brillouin scattering fast light based on doublet broadband Brillouin absorption resonances was numerically investigated by using fast Fourier transform algorithm. The simulation results show that the time advancement, attenuation and broadening factor of signal pulse are readily tailored by relative frequency separation factor of two pump, pump power and length of fiber. The maximum advancement of 80 ps and the minimum broadening factor of 0.87 are achieved for 224 ps Gaussian signal pulse by optimizing relative frequency separation factor of two pump light, power and length of fiber. These will lead to increase the data rate of optical system and reduce the pulse distortion.

In order to reduce interference of modulation noise, a three stages Savitzky-Golay denoising method was proposed applied to the gas concentration inversion based on direct absorption spectroscopy laser detection. Taking near 6 612.939 cm-1 absorption line of NH3 molecular as a test object, the experiment results show that the root mean square error of NH3 original absorption spectrum signal was decreased from 8.53 to 1.01 by three stages Savitzky-Golay denoising method, the SNR of NH3 absorbance profile was increased by 3.3 times; 5% standard NH3 was measured five times in succession, which the average deviation of inversion value was 0.0743%, and the relative standard deviation was 1.4%. The inversion value was better than that of db6 wavelet denoising and non-denoising. The accuracy of gas concentration inversion can be improved when the original absorption spectrum signal was processed by three stages Savitzky-Golay denoising, which can provide reference for the on-line laser detection of high-concentration industrial gas.

From a theoretical analysis, the frequency multiplication factor of 2k microwave signal with a minimum optical sideband suppression ratio of 45.48 dB and a minimum spurious suppression radio of 39.46 dB is generated by properly adjusting the direct current bias points and the modulation index of the cascaded Mach-Zehnder modulators without changing the optical filter. Moreover, the performance of sideband selection with the direct current bias point of Mach-Zehnder modulator, the amplitude and the initial phase difference of the modulation signal deviate from the ideal values is analyzed. Furthermore, the performance is evaluated by simulation experiment. The simulation results validate the feasibility and effectiveness of the proposed approach.

Aiming at the inaccurate transmission estimation in the sky region of the dark channel prior, three Gaussian functions of different scales are used to act on the RGB channels of the hazy image to obtain a "pseudo" dehazing image respectively; Secondly, the adaptive parameter is obtained by using a mixed channel of the hazy image, the parameter together with the minimum filter act on the "pseudo" dehazing image, and then the joint bilateral filter is used to eliminate the texture effect to get the accurate transmission; Finally, using the local atmospheric light estimation method, combined with the atmospheric scattering model to restore the haze-free image. The experimental results show that the method not only reduces the time complexity, but also has obvious image details and good brightness. It also has a good dehazing effect for large-area sky areas and improves the color distortion of the sky area.

In order to make full use of the important features of source images, an infrared and visible image fusion algorithm based on iterative guided filtering and multi-visual weight information is proposed. Firstly,input images are decomposed into base and detail layers by iterative guided filtering. Secondly,binary weight coefficients are synthetically determined by edge information,sharpness and contrast,which are then optimized by guided filtering to reduce noise and suppress artifacts. Finally,the fused image is reconstructed by the base layers and the detail layers on the basis of restructuring rules. Experiments show that compared with conventional multi-scale decomposition methods, the proposed method can better achieve separation of spatially-overlapped features, which can not only make the detail information more prominent,but also suppress the artifacts effectively.

Aiming at the technical requirements of high-frequency and high-precision calibration of optical remote sensing satellites in China, and the current shortage of manual calibration, a hyperspectral ratio radiometer system was developed. The instrument has long-term automatic observation function with a spectral range of 400~2 500 nm. The optomechanical system consists mainly of a front optical system and a spectral module. According to the parameter requirements in the site calibration and the target of automatic calibration, the instrument designs the integrating sphere to measure the total irradiance, and realizes the measurement of the diffuse irradiance by occlusion, and obtains the diffuse ratio data in the satellite calibration. Designing optical lenses to achieve ground radiance measurements for automatic observation of atmospheric-surface radiation characteristics. At the same time, the instrument integrates real-time pre-processing and remote transmission of calibration data. In order to verify the field environment adaptability of the instrument and the reliability of the automated measurement data, an external field comparison experiment was conducted with the traditional method of manually measuring the surface reflectance and the diffuse ratio. The experimental results show that the relative deviations of the total irradiance, diffuse irradiance and direct irradiance measured by the two methods are less than 5%, and the absolute deviation of the diffuse total ratio is less than 0.025%; the overall trend of the measured reflectivity the same, and the deviation of the two is generally within ±1%, the maximum deviation is less than ±2.5%. The hyperspectral ratio radiometer has high automatic measurement accuracy, can replace the artificial measurement of atmospheric radiation characteristic parameters and surface reflectance, and achieve higher measurement frequency. It has broad prospects in the field of remote sensing satellite automatic calibration.

A temperature control system for semiconductor devices is developed, which can be used for the temperature control of semiconductor devices with built-in thermoelectric cooler and of those without thermoelectric cooler and thermistor over a wide variation range of ambient temperature. The hardware part of the system is mainly composed of two parts. For the first part, a main controller module, a temperature acquisition module and a thermoelectric cooler current control module realize the temperature control of the semiconductor devices with built-in thermoelectric cooler. For the second part, an auxiliary controller module, a temperature acquisition module, a metal-oxide-semiconductor field-effect transistor switch circuit module and a thermoelectric cooler realize the temperature control of the semiconductor devices without built-in thermoelectric cooler. For the software, the real-time acquisition of the operating temperature of the semiconductor device is realized by the main and auxiliary controllers, and an integral-limited digital proportional-integral-derivative algorithm is used to adjust the current of the thermoelectric cooler driver to achieve a constant temperature control. Using the developed temperature control system, the temperature control accuracy of a semiconductor laser with a built-in TEC is ±0.01℃, and the temperature stability reaches 0.004 8℃. The temperature control experimental results of a semiconductor source without thermoelectric cooler show that the temperature control accuracy are ±0.05℃, ±0.01℃, ±0.02℃ at an ambient temperature of -18℃, room temperature and 40℃, respectively. The output spectrum of a 1.563 μm laser is measured continuously for 5 hours by the developed temperature controller, which generates a stable peak wavelength. With a 1.653 μm laser, methane detection experiments are carried out by using a temperature controller and the developed controller. A lower detection limit is achieved by the developed controller as compared with the results obtained by the commercial one. The system has the advantages of small size, low cost, easy integration, stable and reliable operation, and has good application prospects in infrared gas detection.

A bent Cassergrain focus was used to connect a daytime imaging system to a 1.2 m aperture vehicular telescope. The system employs a short-wavelength infrared waveband for precise tracking and corrects the global atmospheric wavefront tilt at the same time. Double-pass imaging is applied to the near-infrared waveband to produce the image, while the phase-diversity technique is used to restore the image resolution. The system can detect and correct objects with a magnitude 5 or less at an image resolution that is close to twice the diffraction limit. The observation time is 6 hours longer than that of the adaptive system.

In order to evaluate the jitter affection brought up by flywheel in optical satellite, this paper studies the principles in the jitter affection, promotes a theoretical analytical model and constructs a testbed with high fidelity. By studying the principles in the jitter affection, the transfer fuctions between input disturbances and output image motion are achieved, meanwhile, the harmonical and modal characteristics are proved theoretically. Secondly, a testbed with high fidelity is constructed to measure the real affected image motion. Finally, this paper compares the analytical data and test data and analyzes the reasons that brings in the differences. The results indicate that the harmonical characteristics in analytical data and test data coincide with each other well, the typical harmonic factors contained are almost the same. The modal characteristics are similar at low and medium frequencies within 8% error.

To eliminate the multi-beam interference, a binary and randomly distributed phase was introduced to the Fresnel lens array and a binary phase change of 0 or π is applied to individual Fresnel lens. This change in phase disrupts the phases of the periodic beams, and therefore reduces the effect of multi-beam interference on the homogenized plane. The numerical simulation of the laser beam homogenization were carried out using the Fresnel lens with an aperture of 0.5 mm and the foci of 6 mm, and the array number of 20×20. The simulation results show that the overall uniformity of the target plane is calculated as 90% and the beams energy efficiency can be up to 96%. The designed Fresnel lens array was fabricated using microelectronic technologies. The measured uniformity of the homogenized laser beams at a wavelength of 1 064 nm was 83%, and the beams energy efficiency was 96%. Our results indicate that the introduction of the binary and randomly distributed phase to the periodic microlens array can effectively decrease the influence of interference and improve the uniformity of homogenization of single-mode Gaussian beams.

Femtosecond laser with central wavelength of 1 028 nm, repetition rate of 50 kHz and pulse width of 220 fs is used to write double line and tubular depressed cladding waveguides in Nd3+ doped photo-thermo-refractive glass. The influences of laser power, double line separation and diameters of tubular depressed cladding waveguide on the near-field modes of waveguides are investigated, and the waveguides with better guiding mode are obtained. Refractive index profile is reconstructed by intensity distribution of the near-field mode, the largest positive refractive index change for these two types of waveguides is +7.0×10-4 and +5.5×10-4, respectively. By using the scattering technique, the propagation loss of double line waveguide is about 1.29 dB/cm. The loss of tubular depressed cladding waveguide is less than 1.95 dB/cm by testing the insert loss. Therefore, waveguides inscribed directly by femtosecond laser in Nd3+ doped photo-thermo-refractive glass are promising candidates for the development of integrated optical device.

An experimental system for detecting the damage degree of the imaging optical system by using the cat′s eye echo is established, and the peak power of the cat′s eye echo with the irradiation time is summarized. The change mechanism of peak power of cat′s eye echo is analyzed. The relationship between the peak power of the echo and the damage degree of the CCD is established accordingly. Due to the influence of the reflectance and roughness of the CCD in different damage areas, the research shows that the peak power of the cat′s eyes echoes increase dramatically, then decrease significantly with the increase of the damage degree of the CCD. In practical application, it is possible to judge the damage state of the CCD structure according to this rule by detecting the change of the echo strength of the CCD cat's eye.

Aiming at the non-automatic problem of attitude measurement in monocular vision, an automatic measurement method for monocular visual attitude combining EPnP algorithm and SoftPOSIT algorithm is proposed. Firstly, the pose parameter of the stereo target is calculated by the EPnP algorithm, and the pose parameter is taken as the iteration initial value of the SoftPOSIT algorithm. Secondly, the iterative process of calculating the pose by SoftPOSIT algorithm is combined with the stereo target to realize the automatic measurement of the attitude, and the simulation verifies the validity of the topology to determine the pose. Finally, in order to verify the accuracy of the attitude measurement results, the stereo target is mounted on the two-dimensional turntable with the high-precision two-dimensional turntable as the reference, and the measurement data of the target pose is obtained by controlling the rotation angle of the turntable. The experimental results show that when the turntable rotates the angle from -20° to 20°, the standard deviation of the measurement results of the target attitude angle is 0.20°, and the standard deviation of the measurement results of the attitude angle is 0.27°.

In order to improve the speed and accuracy of the hierarchical convolutional features for visual tracking algorithm, and weaken the influence of the inefficient features in different channels, an adaptive hierarchical convolutional features for visual tracking based on correlation filter framework is proposed. In this paper, we select features from two hierarchical convolutional layers representing objects, and combine the filter training with prediction. For each frame of the video sequence, the correlation filter is trained by features which are screened through the average convolutional feature ratio between the target′s region and non-target′s region in the former frame. Then the object′s position is predicted with the maximum response obtained by the classifier and the target′s features. Finally, we sparsely update the features of the initial frame in accordance with the predicted result. The proposed method is tested on OTB-100 benchmark dataset. The results show that the average distance precision is 91%, along with the average overlap accuracy 64.4% and the average speed 21.7 frames per second, which are 7.3 percentage points, 8.2 percent points higher and 11.3 frames per second faster than the original tracking method, respectively. Besides, the average distance accuracy is 1.2 percent points higher than the continuous convolution operators for visual tracking (CCOT), and the tracking speed is almost 20 times faster than CCOT. This method can improve the speed and accuracy of the convolutional tracking method effectively. It can track stably when subjected occlusion, fast moving and other interferes.

Graphene Oxide (GO) was introduced as a hole transport layer material in a planar heterojunction perovskite battery by solution spin coating. The photoelectric conversion efficiencies of the prepared cells based on GO, GO∶(PEDOT: PSS) composite film and GO/PEDOT∶PSS double-layer film as hole transport layer are 1.86%, 7.35%, and 7.69%, respectively. And the efficiency of the control cell based on PEDOT∶PSS as the transport layer is 7.38%. The main reason is that graphene oxide has insulation properties. When graphene oxide as the anode interface layer, the series resistance of the device increases with the thickness of the graphene oxide film increases, thereby reducing the short-circuit current and efficiency of the battery. In order to improve the conductivity of graphene oxide and its work function, the oxidation of graphene oxide was combined with PEDOT: PSS to form a two-hole transport layer. The battery achieves a high efficiency of 7.69%, which proves that this is oxidation is an effective way for graphene to be used in the hole transport layer of perovskite cells.

To analyze the impact of hybrid gratings on silicon thin film solar cells, the crystalline silicon solar cells with mono shape of grating, syntropy and anisotropy shapes of hybrid grating were designed. And the thickness of silicon layer was unified. By finite-difference time-domain method, the optimal sizes, photocurrent densities and optical absorption of hybrid gratings were optimized, respectively. The results showed that the anisotropy hybrid grating had more optical absorption performance than other structures. Through analyzing the electromagnetic field intensities, the mechanism of optical absorption enhancement of hybrid grating structure was found. Also, the photocurrent density with different grating numbers of component structures was calculated for the anisotropy hybrid grating. Simultaneously, the optimum combination of a triangle convex and a parabola convex in anisotropy hybrid grating was quantified by the factor of absorption enhancement. By varying the ratios of width and height regularly, the photocurrent densities were calculated. Results indicated that the photocurrent density of the anisotropy hybrid structure increased by 62.9% relative to a flat solar cell when the ratio of width was set 1: 1 and the ratio of height ranged from 0.67 to 1.86. The study can provide a theoretical reference for the structure and parameter design of thin film solar cells.

TiO2 nanotubes loaded NiO nanoparticles were prepared by hydrothermal method, which diameter and length are 10~15 nm and 10~300 nm, respectively. The nanotubes were characterized by X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, X-ray photoelectron spectroscopy and uv-visible diffuse reflection spectrum. The photocatalytic activities of the nanotubes were evaluated according to their photodegradation behavior on methyl orange. The results show that TiO2 and NiO grains are well integrated and form the p-n junction, promote the separation of photogenerated electron-hole pairs. NiO/TiO2 nanotubes have good absorption performance in the visible light region result from the strong visible light absorption of NiO. The above two factors lead to a significant increase in photocatalytic performance of NiO/TiO2 nanotubes under visible light. Thereby, the 1 h photocatalytic degradation rate of methyl orange increased from 7.0% of pure TiO2 nanotubes to 95.6% of NiO/TiO2 nanotubes after calcination at 500℃.

MoO3/MoS2 composite structure was prepared by hydrothermal and illumination method. The morphology, structure and photochromic properties of the samples were characterized by TEM, XRD, XPS and UV-Vis spectrophotometer. The samples show nanowire bundle structure. The color of the sample is yellow with the ratio of Na2MoO4·2H2O to C2H5HS is 1∶3. While the color of the samples are blue when the ratio of Na2MoO4·2H2O to C2H5HS is below 1∶3. The prepared samples have photochromic effect. The photochromic property of MoO3/MoS2 is the best with the ratio of Na2MoO4·2H2O to C2H5HS is 1∶2. The excellent photochromic efficiency is attributed to the appropriate band structure of MoO3/MoS2 composite structure, which can effectively separate photogenerated carriers and suppressed the recombination of electrons and holes.

In order to solve the design problem of freeform mirror in ultra-short-focus projection system, a method of freeform surface design for large field of view imaging optical system is proposed, which is called multi-field optimization iteration method. In this method, a reflection plane is used as the design starting surface. Based on the corresponding relationship between objects and images in multi-field, and according to the normal direction vectors of the reflector, the freeform surface is obtained by weighted iterative optimization. Based on the freeform surface obtained by this method, a refractive-reflective combined ultra-short-focus projection objective is designed, which can magnify the 0.65 inch digital micromirror device chip to 100 inch projection screen at the projection distance of 230 mm. The modulation transfer function of the objective system is better than 0.4 at 0.43 lp/mm and the maximum distortion is less than 1%. This method is simple and feasible, which can provide useful reference for the design of freeform surface in large field of view imaging system.

The linear astigmatism balance condition of the off-axis three-mirror optical system was deduced, on that base the off-axis three-mirror reflective system for astigmatism correction with large relative aperture and large field of view was proposed by tilting the optical axis. The field of view is 5°×5°, relative aperture is 1/3.1, entrance pupil diameter is 250 mm and spectral range is 400~2 500 nm. The proposed system was compared with the off-axis three-mirror reflective system of coaxial quadratic aspheric surface and the off-axis three-mirror reflective system of coaxial high-order even aspheric surface with the same optical parameters. The results show that the optical transfer function of off-axis three-mirror reflective system with tilted optical axis is greater than 0.73 at 17 lp/mm in all field of view. It uses conical surfaces and shows obvious advantages in imaging quality. In addition, the processing and adjustment of off-axis three-mirror reflective system with tilted optical axis are analyzed, the tolerance is relatively loose and the structure can be realized.

Based on the generalized Huygens-Fresnel diffraction theory, the intensity expression of the radially polarized spiral Bessel beam is derived. The transmission characteristics, the change of the polarization state and self-reconstruction characteristics of the beam during transmission are studied. It is found that ,by the theoretical analysis and numerical calculation, when the radially polarized spiral Bessel beam is transmitted in free space, the beam is spirally transmitted around the optical axis in the form of a hollow beam and the divergence angle of the beam is zero in a certain transmission region. In addition, the characteristics of radial polarization are maintained during the transmission process. The off-axis spiral transmission characteristic is always maintained and the energy conservation law is followed in the self-reconstruction process of the beam. As the transmission distance increases, the energy originally disappeared in the occlusion region is gradually diffracted to the opposite position of the obstacle occlusion area.

A symmetric Airy vortex beam can be generated by modulating a Gaussian beam imposed on an improved phase pattern, where helical phase factor is introduced in symmetric cubic phase. The experimental results and numerical simulations demonstrate that such beams possess autofocusing characteristic and have a dark core owing to on-axis vortex. Such a special structure causes the beams to rotate in the initial plane. The lager topological charge, the bigger dark area, the greater rotating angle. The positive or negative topological charge only changes the rotating direction. Theoretical analysis shows that in the initial plane, the main lobe of symmetric Airy beams and off-axis vortex have nearly no influence. However, off-axis vortex will gradually appear on one of the main lobes of the symmetric Airy beams during propagation. In addition, the symmetric Airy beams also can embed multiple off-axis vortices which can capture multiple particles without damage. Due to the above characteristics, the beams have potential applications in optical trapping and biomedicine.

Based on the finite difference time domain method, the effects of multiple factors on the scattering angle distribution of redundant nodule particles in optical media films are studied. The complex scattering of redundant nodule particles in optical media film is modeled, and according to the classic half space problem, the total scattering field is decomposed and the corresponding field phase is solved and the mesh division rules are given. The numerical results are reduced to redundant spherical particles and MOM method (Method of Moments) are compared to verify the validity of the program in detail. The influences of incident angle, axial ratio and inlay height h on the differential scattering cross section of Cu and SiO2 inlaid particles with scattering angle under p polarized light are analyzed. The results show that the maximum peak of the differential scattering cross section occurs at the mirror plane of the incident angle. The differential scattering cross section near the specular scattering area decreases with the increase of the axial ratio of flat redundant particles; the rules of influenced by the axial ratio of prolate ellipsoid particles are opposite. In the region of the scattering angle [-90°, -60°], differential scattering cross section is directly proportional to the height of redundant particle inlay. The scattering properties of dielectric particles are affected more by the inlay height.

The light leak from different roughness surface reflected was studied. The bidirectional reflectance distribution function model is established by correcting Torrance - Sparrow model, and the influence factors on the bidirectional reflectance distribution function are numerical calculated. The mathematical model and numerical results are verified by experiments. The main factors affecting the reflected information are the mirror reflection, the diffuse reflection and the absorption of medium, which the mirror reflection includes the reflecting reflectivity of objects, the probability distribution function of micro-elements on reflection surface, the shading factors caused by incident ray incident angle and reflection angle. The main influencing factors is mirror reflection. When the incident angle and roughness are selected and reflection angle is varied from 0 to π/2, reflecting surface bidirectional reflectance distribution function is shown as Gaussian distribution based on the mirror reflection angle under the condition of small reflection angle. If the reflection angle is greater than 1.4 rad, reflective surface bidirectional reflectance distribution function value has increased dramatically and performed a deformation of Gaussian distribution. If the reflection angle of the mirror is selected to receive the reflection information, the bidirectional reflection distribution function of reflecting surface decreases monotonically and changes rapidly with the increase of the roughness of reflecting surface. When the roughness is greater than 0.3, the bidirectional reflection distribution function is close to 0.