In order to solve the problem of deviation in the calculation method of traditional lidar geometric factors， the full field and half field of view functions in the telescope are derived through geometric optics， and the geometric factor is obtained by the ratio of the double integral of the field of view function of the uniformly emitted laser beam area to the cross-sectional area of the laser beam. Considering the effect of the laser optical axis tilt misalignment， the geometric factor calculation equation for the atmospheric detection coaxial lidar is derived. According to the proposed calculation equation， the geometric factor of the typical atmospheric detection coaxial lidar is calculated and compared with the traditional method result. The result shows that the minimum full overlap distance is consistent. Finally， the effects of laser beam diameter， divergence angle， and laser optical axis tilt angle related to excitation-emission on geometric factors are analyzed. The results show that the influence of the laser divergence angle is greater than that of the beam diameter. The method is suitable for the rapid calculation of the lidar geometric factor of the uniformly distributed laser emission beam and can provide a reference for the design of the lidar.

Aiming at the problem that the light spot in underwater wireless laser communication is easily deformed， susceptible to turbulence and to be blocked， firstly， the tracking light spot algorithm of Mean Shift combined with unscented Kalman filter and threshold judgment is used to obtain the real-time position coordinates of the tracking light spot. The analysis results show that when the light spot is blocked， deformed or affected by turbulence， the error between actual movement trajectory and tracking movement trajectory are about 2.1%， 4%， and 1.2%， respectively， which verifies the feasibility of the algorithm. A receiver alignment system is built to track the real-time position of the light spot. The real-time alignment of the receiver and transmitter is controlled based on the relationship of the real-time position and the center position. The alignment accuracy of the system is reflected by the deviation between the actual center coordinates and the center coordinates of the light spot obtained by comparing the alignment system. The experiment results show that the greater the angular velocity of the receiver's motion， the smaller the alignment accuracy.

This paper mainly focuses on exploring the influence of the radio frequency field's frequency and the different atomic coherent situation on the transient effect. It is found that the polarized coherent atoms can still experience a strong transient effect whether the radio frequency filed is resonant or detuned with the Larmor precession frequency， and the transient oscillation frequency depends on the power and frequency of radio frequency field in terms of Ω=Ω02+δ2. Furthermore， the amplitude of transient effect depends on the population of the coherent atoms is explored. The more polarized coherent atoms， the stronger the transient effect presents. At last， we analyze these phenomena by calculating the absorption of beam based on the Liouville equation. There is a good agreement between the experiment data and the theoretical results. These results can provide further insight into the relationship between the coherence of atoms and the transient effect.

To discuss the strain error caused by the relative slip between the flexible Fiber Bragg Grating sensor and the substrate material， ANSYS finite element simulation software was used to analyze the relationship between the relative error of axial strain at each point of the core and the forward pressure. The parameters affecting strain transfer of the sensor， including core material， coating material， substrate material and size were analyzed， and the effect of relative slip on the relative error of FBG axial strain were explored. The results show that the relative error of axial strain at each point decreases with the increase of forward pressure， when the pressure is in the range of ［0.1 N， 10 N］， which presents the trend of small in core and big in two ends. In practical application， it should be combine the positive pressure to select the core material with less elastic modulus and the substrate material with higher friction coefficient， the relative error of axial strain could be less than 10%； select coating elastic modulus 2.4×1010 Pa， 0.062 5 mm thickness， the relative error of axial strain could be reduced to 8.57%； when half length of the FGB is more than 40 mm， the axial strain relative error of the core could be less than 20%， at this point， it could be considered that the coating and silica gel are completely bonded.

In order to explore the influence of the number of cascade stages of the same structure cascade sensor on the sensitivity of the sensor， a comparative study on the same structure based two-stage and three-stage cascaded Mach-Zehnder（M-Z） optical fiber sensor was carried. In the experiment， we fabricated the two-stage cascaded and three-stage cascaded M-Z sensor based on the waist-enlarged structure and misaligned structure. In order to study the difference between the two-stage cascaded structure and three-stage cascaded structure， the strain performance was also measured. The experimental results show that the strain sensitivity of the two-stage cascaded M-Z sensor with waist-enlarged structure is -0.76 pm/με， and that of the three-stage cascaded M-Z sensor is -0.75 pm/με， the sensitivity change of strain is 0.01 pm/με. The strain sensitivity of the two-stage cascaded M-Z sensor with misaligned structure is -0.73 pm/με， and that of the three-stage cascaded M-Z sensor is -0.77 pm/με， the sensitivity change of strain is 0.04 pm/με. Therefore， the sensitivity of the three-stage cascaded structure is not improved obviously compared with the two-stage cascaded structure. The study shows that the multiple cascaded M-Z structures can not improve the sensitivity.

In order to keep the spatial details and reduce the spectral distortion， and to solve the problem that the coefficients of the improved component replacement fusion method are often negative or too small when building the intensity components， a remote sensing image fusion method combining spectral response function and global variance matching is proposed. Based on the general component replacement fusion framework， the intensity component is constructed by using the proportional relationship of the radiation energy response reflected by the spectral response function of panchromatic and multispectral sensors. The physical meaning is explicit， and the mathematical form is simple and clear. At the same time， the spatial detail modulation parameters are determined by using the ratio of global covariance to variance to reduce the spectral distortion and meet the constraints of the general component replacement fusion framework. The proposed method is compared with many mature fusion methods on two groups of different satellite image data， the results show that the fusion image spatial and spectral quality are better.

In order to solve the problem of low contrast and fuzzy details of infrared image， an infrared image enhancement method based on multi-scale convolution combined with adaptive bi-interval luminance equalization is proposed. Firstly， the image is pre-processed by multi-scale convolution； Then， the threshold of image segmentation is solved by genetic algorithm， where the function of maximizing intra class variance and minimizing inter class variance is taken as its fitness function， the double interval histogram with detail information is used to equalize， and the brightness of image is improved by introducing the gray level homogenization of mean square and mean square. Finally， the image with clear details and strong contrast is reconstructed by linear weighted fusion of the detail image extracted by adaptive limited Laplace and the image with brightness enhancement. Compared with conventional methods in the infrared images of different scenes and gray images with abundant details to verify the validity of the proposed method， the maximum growth rates of En， EME and AG in images processed by this method increased from 5.039 1， 13.446 1 and 7.845 0 to 7.163 3， 90.252 5 and 53.617 7， respectively. The experimental results show that this method has better performance.

In order to solve the lacking of calibration means when working in the field， the Beidou Navigation Satellite System（BDS） is used to evaluate telescopes' astronomy and axis orientation precision， which survey the Medium And High Earth Orbit Objects（MHEO）. This research is dedicated to deduce the principle of astronomy and axis orientation， and testify the feasibility of evaluating the electro-optical telescope's accuracy with BDS by analysising the satellites' coverage， orbit pricision and brightness， which has big diameter. Firstly， we interpolate the regular BDS precise ephemeris by Lagrange polynomial， whose data interval is 5 minutes. With coordinate conversion， we get the apparent ascension and apparent declination in the agreement celestial coordinate system， azimuth and pitch in the station coordinate system， which are the true value for astronomy and axis orientation precision evaluation. A MHEO telescope's astronomy orientation precision is superior to 2″ and axis orientation precision is superior to 7″ by this method.

Account for big temperature difference and large dynamic range in the application environment， a compact full-range laser methane probe with a wide temperature range of -40~60℃ is designed. To reduce the volume of probe， cascade structure design is adopted for circuit. Single-chip microcomputer STM32F405 is used to realize laser temperature control， wavelength scanning modulation， digital phase-locked amplification and real-time inversion of concentration information. The circuit system and gas chamber are encapsulated in a stainless steel case of only Φ35 mm×60 mm， with windows in the middle to achieve physical isolation， ensuring intrinsic safety. At low concentration， wavelength modulation technology is used to ensure the measurement accuracy and measurement limit. Direct absorption spectroscopy technology is used to ensure the range and linearity， when the environmental concentration is high. At 25℃， standard atmospheric pressure， the measurement error of low concentration （-4， and the detection limit is 2.24×10-4. Under the condition of allowing baseline calibration or background subtraction， the limit could reach 6.026×10-5. The measurement error of high concentration （2~100%） is less than ±5% of the true value. At the ambient temperature of -40~60℃， 1.2% and 20% standard gases are used for the temperature performance test， respectively. The maximum relative measurement error are -3.3% and -3.15%， which fully met the requirement of national standards. It can be widely used in the urban comprehensive pipe corridor， gas station leakage monitoring， coal mine safety warning and other occasions.

The direct generation of the visible high-order transverse-mode laser was present by employing an off-axis pumping and cavity control in a diode end-pumped Pr：YLF laser. The detailed numerical analysis was proposed based on the intensity characteristic theory about the High-order Hermite-Gaussian （HG） beam and the coherent superposition of different HG amplitudes and phases. In our setup， a blue LD was served as an end-pumped source with a pump wavelength of 442 nm， and a compact plano-concave cavity was designed for lasing. For directly obtaining hollow and high-order HG mode 720 nm laser outputs， we manipulate the resonator of the Pr：YLF laser by employing an efficient off-axis diode-pumping. The experimental results confirmed that the high-order HG beams are generally consistent with the theoretical calculations. In this paper， we experimentally demonstrated an approach for generating the hollow and high-order （HG） mode 720 nm laser beams by manipulating laser modes inside the cavity. Further researches will focus on obtaining higher energy high-order transverse-mode laser outputs， and the method in this paper has potential in the fields of optical manipulation， optical micromachining， and optical communications.

In order to extend the absorption edge of crystalline silicon to the near infrared band to meet the requirement of optical communication，the textured silicon was obtained by irradiation of nanosecond laser pulses. The surface morphology of modified silicon under irradiation with different laser fluence from 0.39 J/cm2 to 24 J/cm2 was investigated. Then， the optical properties including reflectance， transmittance， and absorptance of silicon samples by nanosecond laser irradiation with different laser fluence were measured. The results show that the absorptance below the bandgap of silicon enhances for all the textured silicon samples and it is up to 55% for near infrared light of 1 500 nm. Next， the thermal stability of infrared absorption for the textured silicon samples was investigated. The thermal annealing process at temperatures of 473~1 073 K can slightly reduce the absorptance below the bandgap of silicon and the magnitude of reduction only varied within 10%. Moreover， the dependence of reflectance， transmittance， and absorptance of modified silicon on the annealing temperature was studied on. Lastly， the crystal structures of modified silicon were determined by Raman spectroscope. After irradiation of nanosecond laser pulses， the crystalline silicon surface is disordered and amorphous or polycrystalline phases are formed. However， the crystal quality of textured silicon can be improved by post-thermal annealing process.

In order to improve the effect of CNN feature driven flotation performance recognition under small-scale training set， a method of flotation performance recognition based on adaptive transfer learning and CNN features extraction of foam infrared and visible images is proposed. Firstly， a dual-modality CNN feature extraction and recognition model based on AlexNet was constructed， and the structural parameters of the model were pre-trained through RGB-D large-scale data set. Secondly， a series of double hidden layer automatic encoder extreme learning machine is used to replace the full connection layer of the pre-training model， so that the dual-modality CNN features can be fused and abstracted layer by layer， and then the decision is made by mapping to higher dimensional space through the kernel extreme learning machine. Finally， the floatation small-scale data set is constructed to train the migrated model， and the improved quantum wolf pack algorithm is used for model parameter optimization. Experimental results show that， adaptive transfer learning can significantly improve the accuracy of recognition in small sample data sets， the accuracy of performance recognition using dual-modality CNN transfer learning is 3.06% higher than that of single-mode CNN transfer learning， and the average recognition accuracy of each working condition reached 96.86%. The accuracy and stability of flotation performance recognition is greatly improved compared with the existing methods.

Proposed a partial binary tree twin support vector machine multi-classification algorithm based on optimal classification features （OCF-PBT-TWSVM） to achieve effective classification of non-stationary transient random signals with edge distortion of tooth profile images， and to meet the requirements of real-time gear vision measurement and distortion compensation accuracy Claim. Selected the maximum value vm of the edge dynamic component signal， the position of the edge distortion signal qu， and the edge distortion rate rlv to formed the feature vector，which constituted the training sample set and the test sample set at the same time； defined the variable weight feature vector measure γ with the target of distortion compensation， and completed the construction of the OCF-PBT-TWSVM algorithm according to γ decreasing； used the particle swarm optimization method to optimize the algorithm parameters to optimize the performance of the c1， c2， and g parameters. The test results show that， the final classification accuracy of the OCF-PBT-TWSVM multi-classification algorithm proposed in this paper is 96.96% in the case of small sample data， which has better classification effect and training speed than the PBT-SVM multi-classification algorithm. It is faster and can satisfy the requirements of subsequent distortion compensation measurement accuracy and real-time gear vision measurement.

The effect of temperature change of BBO nonlinear crystal on the photon output angle and conversion efficiency of spontaneous parametric down-conversion is studied， so as to obtain the appropriate operating temperature of BBO nonlinear crystal and reduce the influence of temperature on the long-term stability of the system. The crystal clamping and temperature control system is designed according to the experimental requirements， and the feasibility and reliability of the system are guaranteed by ANSYS thermal analysis. After that， by changing the crystal heating temperature， the relevant photon output angle and the change curve of photon number rate with temperature under different beam masses were measured under the temperature control accuracy of no less than ±0.03℃. The results show that with the increase of crystal temperature， the output angle of relevant photon decreases proportionally with the change of temperature， which is consistent with the theoretical calculation results. Meanwhile， the increase of BBO crystal temperature from 25℃ to 55℃ can increase the photon rate of poor beam quality by about 34%， and the subsequent temperature increase in a small range will greatly increase the background noise of measurement while increasing the photon rate. Based on the comprehensive results， it can be seen that the temperature used by BBO crystal in the working process should be 55℃.

The root mean square of the imaging spot radius is lower than 10 μm in different fields. The design results show that the designed off-axis two-mirror freeform telescopic optical system has good imaging performance entirely with the superiority of compactness and miniaturization， which can be applied in the specific applications of target remote sensing by the onboard or space telescopic optical systems.

A Bessel lens for laser cutting and beam measurement system are designed and developed. Additionally， picosecond Bessel beam is generated by a picosecond pulse laser and the designed Bessel lens， and it is used for the cutting experiment on a piece of silicate glass with the thickness of 1 mm. The results show that， by the incidence of a Gaussian beam with certain diameter on the Bessel lens， the central core diameter and non-diffracting propagation distance of the generated Bessel beam are 3.4 μm and 2.46 mm， respectively. In the cutting experiment， the diameters of the surface micro-holes before glass breaking are smaller than the designed central core diameter of Bessel beam. The designed Bessel lens and beam measurement system in this paper can satisfy the application requirements of laser cutting.

Organic photomultiplier detector with high trap concentration is developed by double doping method. By keeping the optimal doping ratio of C60 unchanged （1.0 wt%） based on the optimized single-doped device （active layer is P3HT：PC61BM：C60）， while doping both C60 and DDQ electron traps， the effects of different DDQ doping concentrations on the trap concentration of the P3HT：PC61BM active layer and the photoelectric performance of the detector are studied.The study shows that the maximum doping concentration of the double-doped C60：DDQ active layer was 1.5 wt%， which is about 1.5 times higher than that of the single-doped C60 active layer （maximum doping concentration is 1.0 wt%）. The trap concentration of the double-doped C60：DDQ device is 2.02×1018 cm-3， which is about 3.5 times higher than that of the single-doped C60 device （trap concentration is 5.83×1017 cm-3）. Under the bias voltage of -2 V， the external quantum efficiency of the double-doped C60：DDQ device is as high as 2015.32%， which is about 10 times higher than that of the single-doped C60 device （external quantum efficiency is 202.60%）. The results show that the double doping method can greatly increase the trap concentration， so as to realize the high concentration trap doping of the active layer.

Although high-strength and bubble-free Si/Si wafer pairs can be obtained by the Si/Si wafer bonding， the oxide-layer-free Si/Si bonded interface is difficult to be achieved. Thus， the Si/Si wafer bonding is difficult to be used in the field of optoelectronics. The effect of oxide layer thickness on the photoelectric characteristics （current， bandwidth， and spectrum） of wafer-bonded Si/Si p-n junction is studied. The factors which affect the performance of the Si/Si p-n junction are clarified by the simulation of carrier tunneling rate， carrier concentration， electric field， carrier velocity， and recombination rate. This may give guidance for the fabrication of ultrahigh-quality Si-based Si avalanche layer and high-performance Si-based avalanche device. The simulation results show that： with the increase of the oxide layer thickness， the carrier tunneling rate decreases， leading to the decrease of the dark current and photocurrent. The recombination rate also decreases and the carriers aggregate in the p-n junction. In addition， with the increase of the oxide layer thickness， the RC time constant of the device increases and the electric field enhances in the oxide layer， leading to the decrease of the electric field， which in turn results in the decrease of the 3 dB bandwidth.

The aim of this paper is to find out the operator for generating fractional Fourier transform in Hermitian polynomial theory with the operator as the argument， and to incorporate fractional Fourier transform into quantum theory. The role of coordinate-momentum exchanging operator is explored in playing FFrT's addition rule. In the whole derivation the generalized generating function formula of operator Hermitian polynomials and the integration method within ordered product of operators are used. The core of operator Hermite polynomial theory is the operator identity HnQ=:2Qn:， which turns the operator of complex special function into power series in normal ordering， as a result，this greatly simplifies calculations.

In order to enhance the intrinsic robustness or prolong the disentangling time of entangled states， the influence of qubi-basis on the robustness of two-qubit entanglement under local amplitude-damping environments is discussed. The decay law and lifetime of entanglement under various qubit-bases are displayed. The optimal qubit-bases in variety of cases are found. When an entangled state is prepared in an optimal qubit-basis， the entanglement decays most slowly and won't disappear in a finite time. The results imply that one could improve the robustness of entangled states by rotating the bases of qubits， which are expected to be helpful for increasing the qualities or efficiencies of entanglement-based quantum protocols.

In the multi-angle dynamic light scattering for nanoparticle size analysis， the weighted Bayesian inversion algorithm is proved to have a good anti-noise capability. However， it suffers from initial value sensitivity and long time-consuming. This paper presents a method of non-negative least squares constrained weighted Bayesian inversion algorithm， in which the results of the non-negative least squares method are used as the prior value as well as the optimization range of the median diameter and peak width of the weighted Bayesian algorithm. The simulated and experimental results demonstrate that this method can improve significantly the convergence and the anti-noise performance of the unimodal particle system. When there is a big noise， the convergence speed is increased by more than 8 times and the distribution error is guaranteed to be within 0.070 9.

The aim of this paper is to obtain the optical constants of the thin film metallic glass in the visible and near-infrared region. Zr-based （ZrCuNiAl（64.13∶15.75∶10.12∶10%at）） thin film metallic glass was prepared on Si substrate using vacuum magnetron sputtering technology at first， then the ellipsometric parameters of the sample at three different angles of incidence were measured by spectroscopic ellipsometry. The optical constants and thickness of the film in the visible and near-infrared region were obtained by fitting the measured ellipsometric parameters using the Drude-Lorentz two-oscillator model. Moreover， the thickness of the sample was also measured by grazing incidence X-ray reflection to verify the reliability of the measurement results of the ellipsometer. The results show that the thicknesses of the sample measured by the two methods are consistent. The Drude-Lorentz two-oscillator model can describe the optical properties of the Zr-based thin film metallic glass in the visible and near-infrared region well. In the visible and near-infrared region， both of Ψ and Δ decrease with increasing incident angle； the real parts of the dielectric constants are negative and decrease with increasing wavelength； the imaginary parts of the dielectric constants are positive and increase with increasing wavelength. The refractive index of the sample is obviously smaller than the extinction coefficient. The refractive index has its maximum at 1 070 nm， and the extinction coefficient has an inflection point around 1 070 nm. It follows that thin film metallic glass has the optical properties of both general metal and glass. The investigatedresults of this paper will be helpful for the investigation and measurement of the optical properties of Zr-based and the other kinds of thin film metallic glass.

Photolithography mask and thermal evaporation deposition technology were used to fabricate a thin film devices compatible with electromagnetic shielding infrared window， which could realize the device to possess the efficient anti-reflection of infrared signals in the band of 3~5 μm and shield electromagnetic signals in the frequency band of 12~18 GHz. The cross-sectional symmetric metal grid microstructures which met requirements were prepared on the double-sided polished Si substrate by photolithography mask and vacuum thermal evaporation deposition technology， the highly efficient anti-reflection infrared in the 3~5 μm band was prepared by ion beam assisted electron beam thermal evaporation deposition technology. In order to improve the transmittance of the metal grid further， an infrared anti-reflection film was deposited on the metal grid coating with a cycle g of 550 μm and different line widths. Results show that the peak transmittance of the infrared anti-reflection film at 3~5 μm is 99.8% and the average transmittance is 99.3% through the measurement of vacuum Fourier infrared spectrometer. The electromagnetic shielding effectiveness in the 12~18 GHz frequency band of the metal grid was measured by vector network analyzer， and obtained the overall electromagnetic shielding efficiency of the compatible electromagnetic shielding infrared window thin film device in the 12~18 GHz band is better than 27 dB， the peak transmittance in the 3~5 μm infrared band is 86.3%， and the average transmittance is 86.1%. On the premise of ensuring the electromagnetic shielding efficiency is unchanged（≥27 dB）， the transmittance of the metal grid films has increased by 37.6%（the grid cycle g is 550 μm， line width 2a is 30 μm）. The improvement of shielding efficiency can be achieved either by adjusting the cycle and line width of the grid， or selecting a substrate material with lower resistivity.