In order to achieve miniaturization of the laser displacement sensor structure, a single-mirror reflective laser displacement sensor structure is used. Sensitivity, working distance, and system structural parameters of this structure are optimized through research. Initially, a single mirror is used in this structure to deflect incident light in the direction of the laser, widening the optical path within the sensor to improve spatial utilization. Subsequently, a genetic algorithm is employed to optimize the design of the sensor's structure, obtaining the optimal parameters under specific constraints. Finally, an appropriate imaging system is designed for validation. The result indicates that, compared to traditional laser displacement sensor, the single-mirror reflective structure can reduce the sensor's longitudinal dimension from 55. 9mm to 31. 0mm while maintaining sensor sensitivity and working distance. This suggests that the introduction of the mirror effectively reduces the sensor's size. This conclusion holds significance for the miniaturization design of laser displacement sensor.

The magnetic field gradient induced transverse relaxation rate of noble gas atom spins has an important role on the sensitivity of the Nuclear Magnetic Resonance Gyroscope. In order to improve the gyro sensitivity, the magnetic field gradient needs to be suppressed. In addition to the environmental magnetic field gradient, the equivalent magnetic field gradient caused by the polarization inhomogeneity of Rb atoms also exists in the cell of the gyro sensor head. Therefore, a main magnetic field homogenization method based on gradient compensation coil and double beam reverse compensation is proposed. A multi field coupling dynamic model including Rb electron spin polarization, nuclear spin polarization and pumping light field propagation is established. The quantitative relationship between the magnetic field gradient of the cubic cell and the relaxation of Xe nuclear spin is obtained by the finite element analysis method. Through experiments and numerical analysis, the equivalent magnetic field homogenization method by the gradient coil and the reverse propagation double beam uniform pumping is studied. The experimental and numerical results show that T2 of 129 Xe is improved from 3. 6s to 5. 7s in a 5X5X5mm3 cell and the polarization uniformity of Rb atom has been significantly improved in both longitudinal and transverse directions. The equivalent magnetic field of 1st order has been significantly suppressed, and the lateral spin relaxation rate of Xe nucleus caused by the residual second-order equivalent magnetic field gradient has been reduced to about 10-4 . s-1.

A microscopic dynamic light scattering measurement system is proposed to meet the demands of detecting the particle size of minute biological samples. Traditional dynamic light scattering techniques typically require samples at the milliliter level, making them unsuitable for detecting minute biological samples. To address this issue, a microscopic dynamic light scattering system was designed that integrates conventional microscopy and dynamic light scattering technologies. By combining these two techniques, the sample volume was successfully reduced to tens of microliters, achieving a two-order-of-magnitude improvement and significantly reducing sample consumption, thus meeting the laboratory's requirements for trace biological detection. To validate the feasibility of the system, different materials and sizes of nanoparticles as well as biological extracellular vesicle samples were evaluated. The experimental results showed that the measurement size errors for polystyrene microspheres particles at 60nm and exosomes particles at 208.6nm were 1.5% and -3.4%, respectively, which were in good agreement with the actual size, confirming the practicality of the system in practical applications.

To meet the requirements for a wide field of view in vehicle-mounted LiDAR systems, a beam scanning system based on micro-motion non-uniform array microlenses has been designed. This system adopts a biomimetic field of view design and incorporates a scanning structure of microlenses and refractive prisms to effectively segment and stitch the wide field of view. By designing the spatial distribution of the microlenses and refractive prisms, a seamless connection of the field of view is achieved. The deflection of the beam is accomplished by the slight displacement of the microlenses and refractive prisms driven by piezoelectric ceramics, completing the scanning of the optical system over a wide field of view. The working wavelength of the scanning optical system is 905nm, and when the displacement of the piezoe-lectric ceramics is 200gm, the horizontal field of view is 112. 5°, and the vertical field of view is 25°. The root-mean-square (RMS) radius of the exit beam is less than 0. 277", and in areas of high resolution, the RMS radius is less than 0.081 *. This solution offers the advantages of compact size, large scanning field of view, and high central resolution,providing a reference for the miniaturization of vehicle-mounted LiDAR scanning systems.

The large image area fluorescence microscopy imaging system can perform one-time imaging of large-size dPCR biological gene chips, but its depth of field (DOF, Depth of field) is small, which limits the object detection depth of the system. The wavefront coding technique is used to effectively expand the depth of field of the large image area fluo-rescence microscopy imaging system without reducing the resolution, which provides technical support for the subsequent one-time imaging of high-throughput multilayer stacked dPCR chips. However, considering that the forward design and simulation of the microscopic imaging system is not suitable for direct depth of field extension analysis,so it is inverted and flipped to analyze the focus depth extension range (i. e. , depth of field) on the image side (original object side). In order to determine the optimal phase plate parameter values, a genetic algorithm was written to link with ZEMAX's API interface, and the phase plate modulation coefficients were optimized, screened, and set in a dynamic interactive manner. A phase plate with a specific coefficient is added to the parallel light path in front of the aperture diaphragm of the large image area fluorescence microscopy imaging system to modulate the wavefront phase of the optical system, so that a consistent intermediate blurred image is produced within a range near the focus. The Wiener filter is used to restore the intermediate fuzzy image, and the simulation results show that the encoded image has a high resolution (up to 6. 5um) within the range of ±10 times depth of field of the traditional optical system, which can realize the depth of field extension of the system. The actual large image area fluorescence microscopy imaging system equipped with a phase plate has a good image restoration resolution (6.5 pm) within the range of ±7 times the depth of field.

The development of a miniaturized, digital, and high-bandwidth optical phase-locked control system is the key to realizing miniaturized narrow linewidth laser light sources for practical applications. However, current general-purpose and special-purpose systems have problems such as relying on commercial platforms, insufficient bandwidth, and low integration. The digital servo system developed is based on field programmable gate array (FPGA) and high-speed analog-to-digital converter (ADC) and digital-to-analog converter (DAC) to implement digital synthesizer, modulator,phase detector, filter and servo Control unit, successfully developed a high-speed, reconfigurable, dual-channel optical phase-locked loop integrated hardware platform, with a system open-loop bandwidth of 2. 63MHz. Combined with the whispering gallery mode (WGM) optical microcavity with high quality factor characteristics, a narrow linewidth laser with an integral linewidth of 20Hz is achieved through the phase modulation optical heterodyne frequency stabilization method (PDH), and the optical closed-loop feedback bandwidth reaches 450kHz. The system has good versatility and scalability, and can be applied to servo locking of various atomic and molecular spectra and optical frequencies.

The space target captured remote sensor is more and more applied in the field of deep space exploration. It can capture the space target quickly and accurately with high-precision multi-dimensional adjustment mechanism. The attitude adjustment of the remote sensor is based on the coordinate system of the adjusting mechanism. At the same time,in order to eliminate the influence of the asymmetric field angle of the remote sensor caused by the inconsistency between the optical datum of the remote sensor and the coordinate system of the adjusting mechanism, the angle matrix between the optical datum and the coordinate system of the adjusting mechanism should be measured when the remote sensor is installed with the adjusting mechanism. Moreover, the space angle between the optical datum of the sensor and the coordinate system of the adjusting mechanism should be adjusted to meet certain tolerance requirements. A method of using laser tracker in the same coordinate system to achieve optical datum and mechanical datum measurement at the same time is introduced, and then the angle matrix between them is established. Then the electronic theodolite monitors the optical datum of the capture remote sensor in real time to realize the accurate installation of the capture remote sensor and the attitude adjustment mechanism, and the installation accuracy can be controlled within 10".

The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) onboard the CALIPSO satellite provides high-resolution vertical profiles of aerosols and clouds, which plays a significant role in studying the vertical distribution of atmospheric aerosols. The domestic historical researches in the CNKI academic journal database on CALIPSO satellite atmospheric aerosol studies are reviewed in this article, and a visual analysis of research progress, hotspots, and trends in this field is conducted based on the Citespace software. The analysis includes historical publication volume, research institution analysis, research author group analysis, citation analysis, co-occurring keyword analysis, burst keyword analysis,and keyword clustering analysis. A comprehensive summary of the progress, hotspots, and trends in CALIPSO atmospheric aerosol research is presented.

With the development of optical technology, higher requirements are put forward for the comprehensive performance of optical lenses. As an indispensable part of lens production, the core processing plays an important role in the comprehensive performance of lenses. The existing core processing requires workers to manually measure and adjust the core device, which requires high technical requirements for workers and slow processing efficiency. Based on Hough transform, this paper proposes a center bias detection algorithm suitable for centering processing to improve the measurement efficiency of centering processing. First, the image in the eyepiece of centering device is captured by an industrial camera, and the image is pre-processed by gratings, noise reduction, interference reduction and binarization according to image features. Then, according to Canny edge detection and Hough transform, the straight line of the cross image in the image is identified, and the intersection point is obtained according to the Angle of the straight line. The actual center bias of the lens is fitted by the least square method, and the center bias detection of the reflection measurement and the transmission measurement is realized. The experimental results show that the algorithm can detect the center bias under two working conditions, and the detection accuracy reaches sub-pixel level. The center bias detection algorithm used in this paper can improve the efficiency and accuracy of center machining.

In order to improve the birefringence and sensing sensitivity of optical fiber, a photonic crystal fiber based on elliptical hole array is proposed. The refractive index distribution of optical fiber is modulated by air holes, which effectively improves the birefringence of optical fiber. Based on the full vector finite element analysis method, the dispersion, limiting loss and temperature sensing characteristics of optical fiber are studied. The simulation results show that the birefringence of the fiber is as high as 1. 92X10-2 when the ellipticity of hole array is 2. The limiting loss is as low as 10-10 dB/km, and the dispersion is about -15. 54ps . km-1 . nm-1. The thermos-optic coefficient of the fundamental mode of the optical fiber is effectively improved by filling liquid for sensitization, and the thermos-optic coefficient is up to 9.5×10-5/C, which can be used for optical fiber high sensitivity temperature sensing.

A method of fabricating optical fiber microcavity based on hydrofluoric acid etching technology is proposed and designed. An all-fiber (Fabry-Perot, F-P) multi-beam interference filter structure is formed by welding a 4. 5mm long single-mode optical fiber. The main interference spectrum period is 20.7nm and the secondary interference spectrum period is 1. 4nm; on this basis, the fiber F-P filter as the frequency selection device constitute an erbium-doped fiber laser system, and narrow linewidth laser output with center wavelength of 1560.40nm, signal to noise ratio of 15. 441dB and 3dB linewidth of 0. 28nm is realized. In the experiment, the optical fiber F-P filter was heated and cooled by the temperature heating platform in the experimental temperature range of 360~430C. The laser wavelength was red-shifted during the heating process, and the temperature sensitivity of the sensing system was 13. 80pm/C, the linear fitting degree is 99. 82%; the temperature sensitivity of the laser sensing system during the cooling process is 13. 36pm/C, and the linear fitting degree is 99. 44%.The experimental results provide a laser system measurement method for high-precision high-temperature sensing.

To improve the measurement accuracy of refractive index of parallel transparent materials, a refractive index measurement method based on Tolansky interference is proposed. Through the analysis of geometric optics theory,the relationship between the lateral displacement of the center of the Tolansky interference concentric ring and the refractive index was established. A parallel transparent material refractive index measurement simulation model was constructed, virtual experimental research on the measurement method was conducted, and the feasibility of the method was examined. An experimental system was built to measure the refractive index of glass sheets, which was compared with other instruments. The experimental results show that after measuring the material rotation angle, interference ring center lateral displacement, and material thickness, the relative error between the calculated refractive index value and the theoretical value is only 0. 11%, providing a new feasible solution for high-precision measurement of refractive index. The uncertain evaluation results indicate that the measurement results of this method are most affected by the thickness of the tested material.

The unstable vibration of the surface stress sensitive film sensing system in the wind tunnel brings large errors to the measurement results. A self-calibration method is proposed to perform vibration correction on the sensing images to eliminate the effect of unstable platform vibration and reduce the measurement errors. The initial displacement containing vibration and effective information is firstly obtained by cross-correlating the original sensing images, then the reference zone mask is obtained by Otsu thresholding method and morphology, and finally the whole vibration plane is restored and vibration corrected using the principle of perspective transformation and the least-squares method. The method involves the sub-zones of the sensitive membrane sensing image as feature points in the calculation, realizes the self-calibration correction of vibration, and enables the sensing system to perform high-precision measurement even on unstable platforms. The validity and practicability of the method are verified by high-speed train experiments, which show that the method has higher accuracy and better robustness than other traditional methods, produces good spatio-temporal resolution images, and reduces the vibration average error by 98% in an incoming flow of 50m/s.

In recent years, fiber optic distributed temperature measurement system has been widely used in the field of ambient temperature, however, in such as power plant boiler temperature from room temperature of 20 degrees Celsius to more than 600 degrees Celsius in a wide range of high temperature measurement scenarios, domestic and foreign fiber optic temperature measurement has few studies and applications. In the face of a wide range of high-temperature fiber optic temperature measurement problems, the use of special copper coated high-temperature optical fiber, built a distributed fiber optic system, with high-temperature box simulation from room temperature to 600 degrees Celsius high-temperature environment, to collect the corresponding information of reflected light. After experiments, it was found that the measured temperature deviation resolved by using the dual-channel demodulation theory formula was large, and the linear fitting widely used in normal temperature applications could not be adapted to a wide range of high-temperature scenarios.For a wide range of high temperature scenarios temperature demodulation, a variety of non-linear calibration methods are used to successfully achieve a wide range of high temperature tracking of optical fiber.

In the sequencer based on the principle of capillary electrophoresis with laser-induced fluorescence, the polarization direction of the excitation light has an impact on the excitation efficiency of Raman scattering and fluorescence.In-depth research on this characteristic is conducted, the influence of optical systems on the polarization state of incident light through theoretical simulation modeling and polarization ray tracing is analyzed, and an experimental system to study the influence of polarization direction of excitation on the excitation results is built, in this paper. The experimental results show that the Raman scattering light intensity of POP-7 polymer as a screening medium will undergo significant changes with the change of polarization direction of excitation light, with a fluctuation value of over 50%, and this fluctuation value will correspondingly decrease with the decrease of excitation light intensity; For multi-color fluorescent dyes,they exhibit complete randomness during the excitation process. Under different concentration gradients, each color of fluorescence has its own response to changes in the polarization direction of the excitation light, but none of them show significant correlation with the polarization direction of the excitation light.

Atmospheric turbulence channels cause random fading of laser link signal power, which is a significant factor affecting the quality of air-based laser communication links. Simulation and performance analysis regarding the degradation of communication performance is conducted due to short-term random fading caused by atmospheric turbulence in air-based laser communication links. The effects of different encoding rates and retransmission frame structures on error correction performance are analyzed. By adjusting the HARQ transmission strategy, it compares the results of transmission performance improvements such as bit error rate and communication bandwidth utilization rate. According to the simulation results, refined retransmission control and changing error correction encoding rates can effectively improve the error correction capability of laser links. By balancing the coding rate and the length of retransmission frames during the HARQ retransmission process, it is possible to significantly improve laser link transmission performance without affecting link transmission efficiency.

The factors of non-linear character of LED, ambient light and channel noise lead to non-linear distortion in visible light communication system, and then the bit error rate of the visible light communication system increases. Aiming at this problem, a new deep neural network model is proposed, and the non-linear distorted symbols of the visible light communication system are unsupervised recovered based on this model. First of all, the mathematical model of the visible light communication system is constructed, and multiple factors of non-linear distortion are analyzed; then, the recurrent neural network is utilized to learn the short term correlation of the visible light signal sequence, and the gated recurrent unit is utilized to learn the long term correlation of the visible light signal sequence; Finally, a dense network is adopted to learn the non-linear mapping relationship between the input visible light signals and the received visible light signals. Simulation results show that the proposed neural network can reduce the bit error rate of the visible light communication system effectively; it also achieves better effect on different modulation orders and different bandwidths.

The Palace Museum currently has many stone heritage. These stone artifacts are placed in the natural environment and have been eroded by the environment for a long time, which can form hard black crust pollutants to remove difficultly on the surface of these stones. It could affect the beauty of stone artifacts and the details of carving seriously.This paper selects two stone components that removed from different areas of the Palace Museum as the research objects.By utilizing these method including scanning electron microscopy, Raman spectroscopy, and X-ray fluorescence technique, the composition of black crust pollutants could be obtained. To avoid the yellowing effect, a dual wavelength laser cleaning technology is used for black crust pollutants by combining infrared with ultraviolet. The energy of the two laser beams should be changed, but the ratio of the energy is constant. The experimental results show that the energy of the infrared and ultraviolet is 16. 8mJ and 1. 2mJ, respectively. The black crust pollutants have good cleaning effect. Comparing the cleaned and uncleaned parts of the stone components, it proves the advantages of laser cleaning technology in removing black crust pollutants from the surface of stone cultural relics. The cleaning effect is evaluated by microscopic methods.

With the research and development of surface plasmon theory and integrated optics technology, the way to enhance the detection sensitivity through the study of enhanced fluorescence properties on the surface of the sensitive membrane of optical sensors is getting more and more attention in the field of biomedical detection. An optical fiber-type fluorescence sensor based on surface-enhanced fluorescence (SEF) is proposed and analyzed through the finite element method. The simulation results show that the field enhancement factor reaches a maximum value of 12. 11 when the gold film thickness is 50nm and the Surface Plasmon Resonance (SPR) wavelength is 566 nm, at which time the fluorescence enhancement effect is better. The designed fiber optic sensor was processed by magnetron sputtering method, and the fluorescence detection platform was built and tested for the fluorescence emission intensity of Alexa Fluor 594 carboxylic acid(AF594-COOH). The experimental results show that the fluorescence intensity excited by the gold-plated multimode fiber is enhanced by a factor of 3. 35 compared to that of the non-gold-plated fiber.