Surface-enhanced Raman scattering (SERS), which combines nanostructured materials with Raman spectroscopy, solves the problem of low sensitivity of traditional Raman scattering technique and provides a new technical means for trace detection. High SERS active substrate is the key to the application of Raman spectroscopy for trace detection. The island nanoporous gold SERS substrate was prepared by dealloying precursor alloy films which sputtered on silicon wafer, and the obtained substrate posses much smaller ratio between pore size and gold ligament size compared with traditional nanoporous gold, resulting in much stronger local electromagnetic field due to improved coupling effect between gold ligaments. The detection limit of the substrate can reach about 10-10 mol·L-1, and the relative intensity of SERS spectrum has a good linear relationship with the concentration, and the dynamic range can reach 3 orders of magnitude. Meanwhile, with uniform structure the substrate exhibits stable performance, and the preparation process shows good repeatability.

High repetition frequency fiber laser plays an important role in the optical frequency comb, industrial processing, ultra-high speed optical sampling and other fields due to its advantages of good beam quality, low power consumption, and high integration. A 163 MHz fundamental repetition rate soliton mode-locked fiber femtosecond laser oscillator is designed and constructed based on nonlinear polarization rotation (NPR) technique. The laser can produce a maximum power of 200 mW at a pump power of 450 mW, with a 30 nm bandwidth and a 786 fs output pulse width duration. By further analyzing the relationship between the pumping power and the output power, it is found that the best operation condition for the laser is at 400～450 mW for the pump power. At the same times, the laser can realize self-starting mode-locking. The proposed laser is of great potential in the application fields like precision spectroscopy and astronomical exploration because of its compact optical frequency comb, high image quality and high imaging speed.

Metalens has the prospective to replace the traditional lens for multifunctional sub-wavelength imaging due to its thinness and ease of integration. The beam deflection angle of the metalens increases with the increase of wavelength and produces opposite dispersion compared to the traditional refractive lens. This form of dispersion is also called "abnormal dispersion" or "negative dispersion". Theoretically, the negative dispersion of the metalens and the positive dispersion of traditional refractive optical devices can be used to fully offset the chromatic aberration of the optical system. Consequently, this study demonstrates the design of an achromatic metalens compound lens based on photoresist material by employing Pancharatmane-Berry (PB) phase metalens as the first lens and traditional spherical lens as the second lens, through finite difference time domain method. The focusing characteristics of the lens at λ = 780～980 nm are investigated by FDTD Solutions (a numerical simulation software) and an exceptional achromatic effect of photoresist metalens compound lens is realized. Compared with the traditional achromatic metalens, the achromatic design is simple and efficient which provides a certain significance for achromatic imaging in the specified bandwidth.

The optical properties of metallic materials change with the thickness of the film thickness, resulting in the change of their spectral characteristics. If the film is deposited by thermal evaporation or sputtering, the neutrality of Ni80Cr20 film is poor when the thickness is too thin or thick. The theoretical calculation results show that increasing the proportion of chromium in Ni-Cr alloy can improve the neutrality of the thin film, while the proportion of nickel needs to be increased for the thick film. As for the opposite spectral characteristics of the thin and thick films, intentional fractionation and increasing the proportion of Ni are proposed to improve the spectral neutrality, respectively. The test result shows that the improved coating process is effective.

Light source is the core component of projector display system. Laser light source has the characteristics of high brightness and long life, but it has the problems of high cost and speckle phenomenon. Combining laser with excited fluorescence as projector light source can effectively solve the problems. In this paper, the YAG phosphor and laser unit are combined into a hybrid light source. The influence of phosphor concentration and operation temperature on the luminous characteristics of the hybrid light source was investigated. The experimental results show that the brightness and chromaticity of the hybrid light source increase with the increase of the phosphor concentration, and the conversion efficiency of phosphor decreases with the increase of working temperature. The research results verify the feasibility of the laser-fluorescence hybrid light source for the projector, which not only reduces the manufacturing cost of the whole machine and solves the speckle problem of the laser light source, but also reduces the precision requirements of the optical components and improves the success rate of mass production.

Aiming at the problem of redundancy caused by the large amount of training sample data in the study of spectral reflectance, a sample classification method based on RGB information is proposed in this paper. Firstly, the color is clustered and the number of clusters is determined. Then, the BP neural network is used to reconstruct each spectral reflectance. The experimental results are evaluated by color difference, root mean square error and fitness coefficient, and compared with principal component analysis algorithm. From the experimental analysis, it can be concluded that the spectral reflectance reconstruction effect is the best when the number of clusters is 7. The average CIE2000 chromatic aberration is 0.836. The average root mean square error is 0.0149, and the average fitness coefficient is 99.82%. Finally, the color blocks with large reconstruction chromatic aberration are optimized. Experiments show that color clustering method can be well applied to spectral reflectance reconstruction.

Semi-floating gate field-effect devices based on graphene have been extensively studied due to their nonvolatile memory characteristics. In this paper, a graphene field-effect device with few-layer graphene as the channel, hexagonal boron nitride as the tunnel barrier layer, and graphene as the charge trapping layer is fabricated. Because of its unique semi-floating gate structure, the transfer characteristic curve has double Dirac points, which are systematically studied. At the same time, we get the stable retention characteristics of the device. Within 200 s, the device program and erase current ratio can be maintained at about 20 μA. Our research is helpful realizing two-dimensional optoelectronic devices based on the semi-floating structure.

In order to manage and control the existing time transmission system and ensure the flexibility, completeness, safety and high availability of the system, this paper designs a complete set of optical fiber time transmission monitoring system. A centralized structure is adopted in the system structure. In terms of functions, it includes five parts: fault management, performance management, configuration management, safety management, and data storage management. The specific implementation methods of each function are explained in detail. The system centralizes management and decentralizes control of each time transmission node at the monitoring node, and stores the data in the database. Finally, a monitoring system is tested on the point-to-point time transmission system based on BTDM-SFSW. Experiments show that the system can monitor the system in real time and deal with faults to a certain extent, which has high reliability.

In order to realize high-speed cutting of silicon carbide (SiC) wafers, stealth dicing experiments were carried out by using self-developed high-energy picosecond pulsed fiber lasers. According to the cross-section topography, surface thermal damage area and edge straightness of the slices, cutting results of the picosecond lasers were analyzed, and the effects of single pulse energy and scanning speed on the slice quality were explored. The results showed that when a picosecond laser with center wavelength of 1030 nm, repetition rate of 100 kHz, pulse energy of 20 μJ, and pulse width of about 100 ps was used for stealth dicing of a SiC wafer with thickness of 360 μm. The quality of the slices can meet the requirements of practical applications. The scanning speed can reach 400 mm/s and the corresponding cutting speed was 44.44 mm/s, which was higher than other related reports.

For optical systems such as fisheye lenses, the object point of the super-large field of view conforms to the imaging law of the plane-symmetric optical system. This paper applies the wave aberration theory of plane symmetry optical system developed by LU to study how to optimize the aspheric imaging system in the optical system of the fisheye lens. First, by calculating the influence of the aspheric coefficients of each optical surface on the wave aberration of the super-large field of view optical system, the several optical surfaces that are mostly affected by the changes in the aspheric coefficients are found. Then ,the aspheric coefficients of these surfaces as variables and the modulation transfer function of the optical system as the evaluation function are used, and the adaptive normalized real-coded genetic algorithm is applied to optimize the fisheye lens optical system. Based on the verification of examples, the method in this paper can effectively determine the position of one or more optimal aspheric surfaces, which has guiding significance for optimizing the fisheye lens system.

The radiation temperature measurement system was constructed by color camera and multispectral camera. The blackbody furnace was used to conduct the temperature calibration experiment, and the calibration data were used to obtain a temperature measurement model based on BP neural networks. The reliability of the temperature measurement model was verified by the temperature measurement experiment of a candle flame, and the results showed that the accuracy of the multispectral imaging temperature measurement system was higher than the color camera temperature measurement system. For the problem of insufficient spatial resolution of conventional radiometric temperature measurement system, a microscopic temperature measurement system was established using a hot stage microscope (HSM) and a multispectral imaging camera. The combustion process of single petroleum coke particles inside the high-temperature hot stage was recorded. The temperature distribution on the surface of petroleum coke particles and the temperature change process with time were obtained.

In order to assemble and test a microstructure TDICCD camera, a dynamic MTF test device was proposed and built. The MTF of the camera is measured by the edge method. After theoretical analysis and experimental verification, the measurement accuracy of the device is better than 5%, which meets the design requirements. The device is used to analyze the influence of the two factors of speed-to-height ratio and drift angle on the image quality of TDICCD camera, and the results are consistent with the theory. The construction of this device satisfies the requirements of the ground dynamic MTF test of the TDICCD camera, and has certain engineering significance.