Surface enhanced Raman spectroscopy (SERS) and tip enhanced Raman spectroscopy (TERS) are commonly used to solve chemical problems on electrochemical surface and interface, and to study cell and organism systems. Using the effect of surface plasmon, we can achieve higher signal enhancement by designing special nanomaterials. In order to improve the spatial resolution, the enhanced electric field at the tip of the needle can push the limit of spatial resolution to 2~5 nm in situ. Through the development of single particle detection methods, the growth of single particles and their interactions are studied. Moreover, on the surface of material, the spectral characteristics of each site on the surface are obtained to track the process of chemical reaction on whole surface, simultaneously. By this approach, we study the differences and relations of chemical reactions between micro-particles and macro-surface. With further improvements in sensitivity, selectivity, reproducibility, temporal and spatial resolution, SERS holds the great promise to be applied in other important applications in biology and medicine.

In order to realize the measurement of lidar echo peak, a peak detection and quantization circuit of echo used in lidar receiver is introduced. It uses the method of echo pulse voltage sampling and holding to keep cooperation with low speed ADC (Analog to Digital Converter) to achieve the high precision quantitation of echo peak. The circuit adopts SMIC 0.18 μm process design. The simulation results show that the dynamic range of sampling voltage is 800 mV, and the error of pulse holding voltage of sampling 3 ns pulse width is less than 3.16%. The quantization precision of 10 bit is realized. The whole circuit sampling period is controlled by external enabling signal and reset signal, which can meet the application requirements of lidar receiver echo peak sampling under different occasions.

A microscopic image vision imaging system composed of a telecentric lens, a ring LED light source, an industrial digital camera and a stepping motion controller is designed to be used for LD coupling lens focal spot detection. The diameter and center of the outer circle of the module, and the center and position of the LD laser focal spot emitted by the LD coupling lens are detected. The focal length of the coupling lens and the eccentricity of the LD are obtained to provide precise positioning for subsequent coupling with the optical fiber. The experimental data show that the standard deviation of the eccentricity measurement of the system is less than 5 μm, and the standard deviation of the focal length measurement is less than ±0.1 mm. The relative position relationship between the focused spot and the base circle center can be accurately obtained. The experimental results are accurate and the measurement efficiency is high.

In order to improve the off-screen distance of holographic optical element integral imaging 3D display, a method to enhance the off-screen distance by using computational-generate holographic wavefront design and modulate the wavefront divergence angle of each imaging pixel is proposed. Through computer simulation of the designed wavefront, 66.0 mm continuous 3D depth of field is obtained. Optical reconstruction experiment based on spatial light modulator achieves 140.0 mm integral imaging off-screen display and 75.0 mm continuous 3D depth of field. This method can provide a good method for holographic optical element integral imaging 3D display to enhance off-screen distance, 3D resolution and 3D depth of field.

In view of some industrial diameter measurement scenes where the camera cannot be installed on the end face to be measured, a cylindrical workpiece diameter measurement system is designed, which consists of three linear lasers, an image lens and an area array CMOS camera. It is placed on the ground, projectes and images obliquely. A measurement system is set up. The sub-pixel endpoint coordinates from the image are obtained. The calibration equation is substituted to solve the world coordinates, and the diameter to be measured through the geometric model is calculated. The experimental results show that the system can accurately measure the diameter of the workpiece near the designed value, and the measurement accuracy is within ±0.1 mm, which meets the high precision requirements of industrial measurement.

The phase unwrapping algorithm for path correlation is sensitive to strong noise, so it cannot unwrap the phase accurately. Therefore, in recent years, a phase unwrapping method based on deep learning has been proposed. Optical phase is usually characterized by Zernike polynomials. However, the training data obtained by simulation has class imbalance problem, which will lead to poor segmentation effect and even failure to demodulate subsequent package phases. A DeepLabv3+ network structure is presented with optical wrapping phase data as the training sample and different loss functions as the training samples. The experimental results show that the improved loss function can improve the segmentation accuracy to a certain extent and provide the possibility for the subsequent high-precision phase unwrapping.

Micro-grating accelerometers have the advantages of anti-electromagnetic interference, high precision, low power consumption, small volume and so on. They have wide application prospects in the fields of geophysics, gravity assisted navigation, oil and gas exploration and seismic detection. In order to suppress cross-axis interference, the design of a highly symmetric micro-electro-mechanical system sandwich accelerometer using a double-device-layer silicon-on-insulator (D-SOI) wafer is introduced in this paper. The COMSOL finite element simulation analysis shows that cross-axis sensitivity is only 0.01% when the double-device-layer thickness difference is 0.5 μm. The modal separation radio is increased by 5.3 times compared with traditional structures, which effectively improves the resistance to high-order mechanical modal disturbance. Based on this design, the features of static and magnetoelectric feedback methods are discussed. According to the structure and electrical specifications, magnetoelectric feedback method is adopted to improve the linearity range.

Based on the problem of power signal output instability in the process of contactless grid connected power supply of photovoltaic power generation system, an automatic control method of contactless grid connected power supply is proposed. Firstly, the corresponding hardware equipment, including controller, inverter and driving equipment, is installed in the photovoltaic power generation system and grid connected power supply line. Secondly, the power supply transmission link is formed by non-contact grid connected way. The current signal and voltage signal in the power supply system are automatically monitored by the installed hardware equipment. Based on the monitoring results, the current balance and voltage balance of grid connected power supply are respectively in the two aspects of maximum power supply. The automatic control of grid connected power supply of photovoltaic power generation system is realized. In order to test the performance of the design control method, the experimental results show that the non-contact grid connected power supply automatic control method of photovoltaic power generation system can reduce the floating range of supply current and voltage.

The response characteristics of CMOS pixels will be affected by factors such as production process, dust and damage, which in turn affects imaging quality. It is necessary to develop a method that can efficiently and quickly detect the location and area size of abnormal pixels in image processing. The response characteristics of CMOS pixel is analyzed in this paper, and a pixel classification method based on K-Mean algorithm according to the difference of pixel value is proposed. This method both effectively detect the abnormal pixels and classify them. Experimental results show that this method can effectively detect the types, position and size of abnormal pixel. Compared with traditional “3[σ]”method , this method run with faster detection speed in finding the abnormal pixel region and more accurate positioning.

According to the characteristics of object edge information and noise in infrared image, a bidirectional order filtering algorithm based on statistical sorting is proposed to find the best balance between denoising and keeping image edge information and small target. The FPGA IP module of bidirectional sequential filtering has been widely used in infrared products. It can effectively filter the salt and pepper noise in infrared images, reduce the fixed residual after nonuniformity correction and the electronic noise of signal processing circuit. The application results show that the proposed algorithm has strong filtering ability and less loss of image details, The designed FPGA IP module has less delay and stable timing performance.

Optical inspection of convex aspheric surfaces, especially off-axis convex aspheric surfaces, is always a difficult point in aspheric surface machining. A modified Hindle method is developed to solve the problem of machining inspection of convex aspheric optical elements, which is difficult to solve the deficiency of the classical Hindle method, such as the need of large aperture auxiliary spherical mirror and the presence of center occlusion. In this paper, a compensator set with special structure is designed for the detection of large diameter off-axis convex aspheric surfaces, and the processing and adjustment of compensators are analyzed, and the simulation optimization and tolerance analysis are carried out for the whole compensation detection system. Meanwhile, this design can be extended to the detection of larger diameter convex aspheric surfaces.

In order to meet the needs of fisheye lens in low illumination environment, a low-light level night-vision fisheye lens applied to 2 inch low-light level night-vision camera is designed with ZEMAX. The structure includes window lens, which consists of 7 groups of 10 lenses. All of the lens are optical glasses except window lens. It is characterized by common, good performance and low cost. The effective focal length is 9.5 mm, F number is 1.8, field of view (FOV) is 170°, image height is 21 mm, the optical system total length is 90 mm, the maximum diameter is 56 mm, and the back working distance is 10.4 mm. Its modulated transfer function(MTF) in all fields is higher than 0.36 at 46 lp/mm. The absolute value of the full FOV f-θ distortion is less than 30%, the field curvature is less than 0.15 mm. The image quality of the lens is very good.

In order to reveal the law of image rotation caused by reflective two-dimensional fast-steering mirror in the optical system, and provide a mathematical model for optical offsetting image rotation, a typical application of reflective two-dimensional fast-steering mirror is constructed. By using the mathematical analysis method of space vector rotating around the axis and the reflection imaging law of planar mirror, the reflection image vector model of typical application scene of reflective fast-steering mirror is established. According to the vector model of the reflected image, the mathematical model of image rotation in the observation plane is given. The mathematical model and physical causes of image rotation in two-dimensional fast-steering mirror scanning with single axis and double axis are analyzed, and the simulation results of image rotation angle are given. It lays a theoretical foundation and provides an accurate mathematical model for the optical offsetting image rotation of the optical system based on two-dimensional reflective fast-steering mirror.

The change of the band gap and refractive index of SiO2 with strain is analyzed by using the first principles method, and the change of photoelastic coefficient with strain is further calculated. The results show that when the tensile strain along z axis increases, the band gap of SiO2 decreases. When the compressive strain along z axis increases, the band gap of SiO2 firstly increases and then decreases, reaching a maximum value when the compressive strain is 2%. When the refractive index changes from tensile strain to compressive strain, the refractive index increases gradually. Each component of the photoelastic coefficient has different trends with the change of strain. The results of this paper are helpful to the optimal design of related devices.

LCD industrial instrumentation, automobile instrumentation have stricter and stricter requirements for high-temperature working performance. The phenomenon of image missing at high temperature seriously deteriorates the display performance of the product. According to the actual situation encountered in the LCD application, the cause of high-temperature image missing has been studied. Through theoretical analysis and experiments, the reasons for high-temperature image missing are found in three aspects： driving frequency, N-LINE setting, liquid crystal voltage, and impurity ions in the cell. The frequency and N-LINE settings can reduce the effect of the DC component electric field, the liquid crystal voltage can reduce the strong polar molecules, and the less impurity ions in the box can reduce ion accumulation. Through experimental research, the product can meet the requirement of 500 hours work at 70°C without missing. Through parameter optimization, the images missing phenomenon of high-temperature is effectively improved, and the product quality is improved through the improvement, and good economic benefits are achieved.

Laser wireless energy transmission plays an irreplaceable role, researchers have never stopped working on high-efficiency laser wireless energy transmission systems. Based on the situation that different obstacles exist in the laser transmission process in space, this will affect the output characteristics of the laser wireless energy system. Therefore, it is of great significance to explore the influence of shielding on the photoelectric conversion efficiency. In this work, the effect of the masking degree on the performance of the 6-junction laser cells is analyzed by theoretical simulation of the 6-junction equivalent diode model and experiment. In addition, the I-V curves of the 6-junction GaAs laser cells were experimentally measured by using an 808 nm wavelength laser as the light source in four scenarios of shade degree under five different powers, then the relation between the shade and the photoelectric conversion efficiency is obtained. Experimental results show that the short-circuit current, photoelectric conversion efficiency and open-circuit voltage of the 6-junction laser energy conversion chip decrease with the increase of shielding degree at the same optical power. The theoretical results are consistent with the experimental results. At the same time, an effective optimization strategy for obtaining higher power is given by optimizing the circuit in the presence of masking. In theory, the optimized circuit can obtain higher maximum power point than the series circuit, and the correctness of the theoretical simulation is verified by experiments. Thus, it can be concluded that the shade degree plays a crucial role in obtaining the maximum power of the receiver.

A novel equivalent error calculation and compensation method of inertial sensors is proposed to solve the problem that the navigation error diverges with time in rotating inertial navigation system (RINS). Based on the error model of RINS and the equivalent error characteristics of RINS, DC component are analyzed, earth oscillation term and time divergence term of the navigation longitude and latitude error are analyzed. The main equivalent inertial sensor errors are calculated. With the compensation of the equivalent inertial sensor error, the longitude error is suppressed and the longitude error is reduced from [0.4] to [0.15]. Furthermore, the navigation accuracy is increased by 62.5%. These experimental results illustrate that the divergence of the longitude error can be suppressed, and the DC component and the earth oscillation amplitude of latitude error are reduced by utilizing this novel method, which realize the improvement of the navigation accuracy.