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Cui D.,Nanjing University of Science and Technology | Cui D.,Xian Institute of Applied Optics | Ren L.,Nanjing University of Science and Technology | Shi F.,Nanjing University of Science and Technology | And 6 more authors.
Chinese Optics Letters | Year: 2012

A halo tester is designed to analyze the halo formation in low-light-level (LLL) image intensifiers and the influencing factors on halo size. The tester is used to collect a 0.1922-mm hole image directly using a CoolSNAP K4 charge-coupled device (CCD) in a darkroom under illumination conditions between 10 -2 and 10 -4 lx. The practical measurement result shows that the amplification ratio is 343.4. Then, the super second- and third-generation image intensifiers are placed after the hole, and the halo sizes of the hole images on the screens are determined as 0.2388 and 0.5533 mm, respectively. © 2012 Chinese Optics Letters. Source


Shi F.,Nanjing University of Science and Technology | Shi F.,North Night Vision Technology Group Co. | Shi F.,Light Technology | Zhao J.,Nanjing University of Science and Technology | And 5 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2012

Based on the theoretical models of computing the photocathode optical performance, quantum yield and integral sensitivity, the photoemission characteristics of the domestic and ITT's transmission-mode extended blue GaAs photocathodes, namely the cathode optical properties and performance parameters, were respectively investigated. The compared results show that the integral sensitivity of the domestic transmission-mode extended blue photocathode has achieved 2100 μA·lm -1, still falling behind the ITT's integral sensitivity of 2750 μA·lm -1. The reasons for the difference in quantum yield curves are that, on one hand, the thickness of GaAlAs window-layer and the Al mole fraction play a critical role in the short-wavelength response, especially in the extended blue region. On the other hand, the cathode performance parameters such as electron diffusion length and back interface recombination velocity work on the long-wavelength and short-wavelength response. All these factors are subject to the backwardness of basic industrial manufacturing level. Source


Shi F.,Nanjing University of Science and Technology | Shi F.,North Night Vision Technology Group Co. | Shi F.,Light Technology | Zhang Y.-J.,Nanjing University of Science and Technology | And 5 more authors.
Chinese Physics Letters | Year: 2011

The quantum yield formula for uniform-doping GaAlAs/GaAs transmission-mode photocathodes is revised by taking into account the light absorption in the window layer. By using the revised quantum yield formula, the domestic and ITT's experimental quantum yield curves are fitted and the fitted curves match well with the experimental curves. In addition, the fit results show that the integral sensitivity and quantum yield of domestic image intensifier tube has achieved 2130μA/lm and 45%, nearly reaching ITT's third generation level in 2002, whereas the discrepancy in cathode performance is mainly embodied in the electron diffusion length and back interface recombination velocity. © 2011 Chinese Physical Society and IOP Publishing Ltd. Source


Cheng H.,Changchun University of Science and Technology | Cheng H.,Light Technology | Cheng H.,North Night Vision Technology Group Co. | Duanmu Q.,Changchun University of Science and Technology | And 5 more authors.
Optoelectronics and Advanced Materials, Rapid Communications | Year: 2012

In order to match the laser working at 1.06 um, a GaAlAs/InGaAs photocathode material was grown by molecular beam epitaxial and was fabricated in the form of transmission-mode GaAlAs/InGaAs photocathode module. It is shown that the integral sensitivity is 575 pAlm-1 and the radiant sensitivity at 1.06 pm is 0.043 mAW1 for the GaAlAs/InGaAs photocathode module. Comparing with the optical properties of the GaAs photocathode module and the photoemission performance curves of the other InGaAs photocathode respectively, it is indicated that the GaAlAs/InGaAs photocathode module prepared in this paper can respond shifting to the infrared waveband, the radiant sensitivity at 1.06 pm is higher than that of Russia's photocathode, and the integral sensitivity is higher than that of US Andor's photocathode. The results show that the parameters of the GaAlAs window layer and the InGaAs active layer should be improved to design in order to decrease the shortwave response and further increase the longwave response. Source


Wang L.,Light Technology | Shi F.,Light Technology | Cheng H.,North Night Vision Technology Group Co. | Niu S.,North Night Vision Technology Group Co. | And 4 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

The photocurrent attenuation of GaAs photocathode within one hour after activation under three different vacuum pressure (5×10-9Pa, 5×10-8Pa, 5×10-7Pa) were recorded by automatically activated monitor. The results show that: the photocurrent quickly descend in the beginning and then descend linearly at a low slope; the amplitude of the quickly descending area were 10%, 14.74% and 36%separately, with the respective slope of the linear descending area were-0.00653,-0.01132and-0.02. Three samples€™ gas components of H2, CH4, CO, H2O, O2, CO2 etc under the same vacuum pressure (5×10-8Pa)during photocurrent attenuation were collected by quadrupole mass spectrometer. By comparing the gas components content and the attenuation law of the photocurrent, it has been found that H2O and H2 had a greater impact on the stability of GaAs photocathode in the ultra-high vacuum environment and H2O was the predominant effect. This paper has important guiding significance and reference value in studying the stability of GaAs photocathode and the improvement of semiconductor photocathode process. © SPIE. Downloading of the abstract is permitted for personal use only 2015. Source

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