In order to study the photoluminescence characteristics and irradiation damage of Lumogen (C22H16N2O6) film in the vacuum ultraviolet band, a thermal resistance evaporation method was used to prepare a Lumogen film with magnesium fluoride as the substrate. Vacuum ultraviolet fluorescence spectrometer, atomic force microscope (AFM), scanning electron microscope (SEM), ultraviolet-visible spectrophotometer and other instruments were used to measure the photoluminescence characteristics, attenuation of fluorescence intensity, surface morphology, transmittance, etc. The experimental results show that the excitation wavelength in the vacuum ultraviolet band is 160 nm; the emission peak width is 500 ～ 620 nm; the peak position is at 528 nm. After continuous irradiation at the excitation wavelength of 160 nm for 20 hours, the fluorescence intensity at the emission peak position decreases from 8.76 to 0.83, and the overall decrease is 90.5%. The values of the root mean square (RMS) smoothness increases from 10.96 nm to 14.96 nm. The high photon energy of 160 nm vacuum ultraviolet light excites the fluorescence in Lumogen molecules The chromophore －OH breaks and the film surface is damaged, causing irreversible damage. The transmittance of the Lumogen film irradiated by vacuum ultraviolet light in the 250 ～ 450 nm band decreased by about 50%.The research results show that under continuous high-energy vacuum ultraviolet light irradiation, the surface of the film will be damaged and the optical performance will deteriorate. This provides a reference for its application in the field of ultraviolet detection devices and aerospace.

Photoacoustic imaging is of great significance for the diagnosis and treatment of cardiovascular diseases because of its unique imaging principle, function and resolution. In this paper, we systematically introduced the principle and applications of photoacoustic blood flow velocity measu rement under three principles of photoacoustic Doppler, photoacoustic microimaging and photoacoustic correlation spectrum to provide some reference for researchers in this field.

In order to estimate the target scale in real time, avoid multi-scale test and improve the speed and accuracy of target tracking, a new optimized target tracking algorithm is proposed. By introducing the regional proposal network with good tracking effect into the common siamese network, and introducing the strip pooling module and the efficient channel attention module in the algorithm, we can deal with the scale difference of objects and the severe deformation in the tracking process. The proposed algorithm achieves 0.833 accuracy and 0.658 success rate on OTB100 dataset, 0.411 EAO index on VOT2016 dataset, and 0.275 EAO index on VOT2019 dataset.

In the diagnosis of glaucoma, segmentation of optic cup and optic disc based on digital fundus image is a common diagnostic method. In order to segment the cup and disc accurately, we proposed a segmentation method based on the improved U-Net. Compared with the traditional U-Net, a residual block was used to improve the down sampling part, and convolution part was used to improve the skip connection, so that the network could obtain more sufficient feature information. The Dice and IOU of the optic disc segmentation model and the optic cup segmentation model on DRISHTI-GS data set reached 98.3% and 97.2%, 93.2% and 88.5%.

To design a bio-sensor for DNA detecting, we proposed a polarization free transmission type guided mode resonance biosensor with high sensitivity in visible wavelength was proposed for DNA detection with the FDTD software simulation based on the rigorous coupled wave theory and equivalent theory. When ssDNA was detected, the resonance wavelength was 481.46 nm. When dsDNA was detected, the resonance wavelength was 490.11 nm. When no DNA is present in the detection area, no transmitted light appears. Hence, it can be used to distinguish between single and double-stranded DNA. This bio-sensor can maintain the biological activity of the sample and avoid physical or chemical damage of the sample, which is convenient for multiple analysis and detection, and owns potential applications in the field of biological detection.

Based on the McKenna burner, a dual light path imaging system was developed to synchronously collect the backlight projection profile image and the self-luminous light intensity distribution during the combustion of pulverized coal particles. Experiments were conducted on bituminous coal and anthracite particles separately, volatile ignition, soot formation, coke ignition were observed simultaneously, and corresponding analysis was conducted. It was found that the two coal types were mainly in homogeneous and heterogeneous ignition pattern, respectively. The separation phenomenon of solids and volatiles due to the interphase velocity difference between phases was observed during the burning of coal particles, and an image processing program was applied to calculate the corresponding motion speed. The study provides a reference for further quantitative analysis of the ignition and combustion characteristics of pulverized coal particles.

CsPbBr3 nanoplatelets (NPLs) with different thickness (3-5 monolayers) were synthesized by ligand-assisted reprecipitation at room temperature to study the nonlinear optical absorption properties in the near-infrared-II window. The nonlinear three-photon absorption properties of CsPbBr3 NPLs were investigated by Z-scan technique using a laser with central wavelength of 1030 nm, pulse width of 6 ps and repetition of 25 kHz. The experimental results show that the nonlinear three-photon absorption cross section of CsPbBr3 NPLs is significantly increased due to the enhancement of quantum confinement effect with decreasing the thickness of NPLs. The three-photon absorption cross section of the 3 monolayers NPLs is 4.1 × 10-71 cm6s2photon-2. This study shows that CsPbBr3 NPLs have excellent nonlinear multiphoton absorption properties in the near-infrared-II window, and can be applied in the field of multiphoton fluorescence imaging.

In order to display the luxmeter of illumination and the induced voltage of illuminance, we design illuminometer based on a single chip microcomputer simulation, and the photoelectric conversion circuit, amplifier filtering circuit, A/D conversion circuit, display circuit and alarm circuit. The hardware circuit system is built. The debugging is completed. Experiments show that the system of illuminometer can display the induced voltage effectively.

The super lens with refractive index of -1 can achieve perfect imaging theoretically, but the photonic crystal with equivalent refractive index of -1 does not meet the conditions of permittivity ε=-1 and permeabilityμ=-1. The impedance of the photonic crystal does not match the free space, and the incident light at some angles cannot be coupled with the Bloch wave in the photonic crystal, resulting in the loss of these light information. It limits the imaging resolution. In order to improve the imaging resolution, a subwavelength grating is set on the surfaces of the photonic crystal and the coupling efficiency of the incident light to photonic crystal is improved. By adjusting the grating period, high spatial frequency components are involved in the imaging and the transmission of low frequency components is suppressed. With the subwavelength grating set on the surfaces, the imaging resolution of photonic crystal increases from 597 lp/mm to 850 lp/mm, which breaks through the diffraction limit.

Aflatoxin B1 (AFB1) is a fungal toxin common in crops and it is the most toxic of all mycotoxins which can cause cancer. Thus, quick and effective detection of AFB1 is important for food security. Here, a simple and sensitive optical sensor based on surface-enhanced fluorescence (SEF) technique was designed to detect AFB1. We used nanoporous gold (NPG) as the substrate. The AFB1 aptamer (Cy5-DNA1) and AFB1 complementary aptamer (SH-DNA2) were successively assembled on the surface of NPG to form the optical sensor for AFB1. Competitive binding between AFB1 and Cy5-DNA1 released Cy5-DNA1 from NPG, leading fluorescence intensity of Cy5 to fall. AFB1 was detected by monitoring the variation of the fluorescnece intensity of Cy5 and the final detection limit was 10-7μg/L with a linear dynamic range 4 orders of magnitude.

In order to solve the problem of long-time operation of a fiber-based frequency comb, the control method of locking the repetition rate (fr) and carrier envelope phase offset frequency (f0) of optical frequency comb is improved. Two thermo-electric coolers (TEC), an upper one and an lower one, are used to control the temperature of frequency comb. By adjusting the TEC temperature, the stability of fr and f0 can be confined in the range of 10 and 600 Hz, respectively. Then, fr and f0 were further stabilized by the feed-back control of the optical path and the pump power, respectively. Finally, in 170-hour operation, the standard deviations of fr and f0 were measured as 0.83 and 280 mHz, respectively. The results show that the method can realize the long-term operation of the optical frequency comb and enhance its adaptability to the environment.

In order to achieve the fine analysis and classification of the defects on the panel, the apochromatic objective with a numerical aperture of 0.42 in the visible spectrum and illumination optical system were designed. First, the objective lens was designed with reasonable structure optimization, optical focal length distribution and material selection, and the MTF curve is closed to the diffraction limit. Secondly, the illumination optical system is designed by the scheme of Kohler illumination. Simulating optical system with Lighttools software.The experimental results show that the resolution of the optical system can reach 0.775 μm and the illumination uniformity can reach 98%. The results are consistent with the actual test results and meet the requirements of high-precision panel inspection.

In order to save time and researchers' energy, computers are used to assist in the detection of cells or nuclei. In this paper, a derivative network U-net of convolution neural network is combined with image processing to detect nucleus. The result shows that the accuracy is 0.82, the recall rate is 0.83, and the F index is 0.83, which has good recognition and segmentation effect.

In the laser inertial confinement fusion experiment, aiming at the urgent need for quick and accurate positioning of the diagnostic experiment equipments, the quick positioning and aiming method of using the laser tracking measurement system is proposed. The four-beam laser tracking measurement system is used as the aiming and positioning equipment, the mathematical model of the measurement system is developed, and the theoretical calculation of the aiming and positioning accuracy of the measurement system is carried out based on the least square method. When the measurement error of the laser trackers is 5 μm, the theoretical calculation angle error is 0.7492″, and the distance error is 11.2083 μm. When the measurement error is 10 μm, the angle error is 1.12″, and the distance error is 18.2167 μm. The theoretical calculation results indicate that the aiming method based on the laser tracking measurement system meets the quick and accurate positioning requirements of the experimental devices in the laser inertial confinement fusion. It provides theoretical guidance for using laser tracking measurement system as aiming and positioning equipment in China’s laser inertial confinement fusion device in the future.