Detectors|10 Article(s)
Transient Luminescence Characteristics of Random Laser Emission Based on Electron Beam Pumping Perovskite Nanocrystals
DU Peng, MU Yi-ning, REN Hang, FAN Hai-bo, ZHU Yan, LI Yan-zheng, and IDELFONSO Monroy
In order to meet the requirement of instantaneous imaging technology for transient optical system, a method of instantaneous luminescence based on perovskite nanometer crystal random maser is proposed in this paper. Based on the preparation and characterization of CsPbBr3 nanometer crystal films, the preparation methods and means of similar active films are analyzed. Combined with the application needs, this paper designed the electron beam pumping structure with microchannel plate as the core, and verified the maser effect of CsPbBr3 nanometer crystal film under electron beam pumping through experiments, and analyzed its maser principle and physical phenomenon. Finally, the instantaneous advantage of CsPbBr3 nanometer crystal thin film is verified by instantaneous optical pumping. In the instantaneous detection system of the new developed film, not only has good transient characteristics and time resolution, but also can use the electron beam pumping to induce laser to form the second stage of light amplification, thus improving the overall detection ability of the device.
Acta Photonica Sinica
  • Publication Date: Apr. 25, 2020
  • Vol. 49 Issue 4 0404001 (2020)
Remote Sensing and Monitoring of Industrial SO2 and Carbon Black Particles with Ultraviolet Imaging Technology
DUAN Wei-min, XIONG Yuan-hui, CHEN Zhen-wei, YU Guang-bao, LIU Lin-mei, LI Fa-quan, and WU Kui-jun
In order to monitor industrial chimney emissions accurately and effectively, based on the optical properties of SO2 and carbon black particles, a dual-channel ultraviolet imaging remote sensing monitoring system was developed. The center wavelength of the two spectral channels were set at 310 nm and 330 nm, respectively. The SO2 concentration image was obtained by the optical thickness difference of the two channels, and the particles concentration image was obtained by the 330 nm channel. With the plume speed obtained from the density image by the Optical-flow method, the emission rates of SO2 and carbon black particle were calculated from them. The results show that the emission rates of SO2 and carbon black particles from the industrial chimney are 72.48±3.16 kg/h and 6.33±1.18 kg/h, respectively. In this experiment, the SO2 and carbon black particles emitted from industrial chimney were monitored by ultraviolet cameras simultaneously. A high time and spatial resolution was provided with dual-channel ultraviolet imaging remote sensing monitoring in this experiment, and the measurement results are accurate and intuitive. This method has obvious technical advantages and great application prospects in remote sensing of industrial exhaust, ship exhaust and volcanic eruption pollutions.
Acta Photonica Sinica
  • Publication Date: Apr. 25, 2020
  • Vol. 49 Issue 4 0404002 (2020)
Research on the Test and Calibration Method of a Focusing X-ray Detector for Pulsar Navigation
ZHOU Qing-yong, WEI Zi-qing, JIANG Kun, LIU Si-wei, ZHENG Wei, SHI Yu-feng, WANG Yi-di, YANG Yan-ji, HU Hui-jun, JIN Dong-dong, SONG Juan, SUN Peng-fei, and SONG Hao-lei
A testing method for X-ray detector is proposed through the study of the characteristics of pulsar radiation signals and the analysis of space observation requirements. Firstly, based on the photon radiation model, the probability formula of X-ray photon under detection is deduced, and the influences of different source flux and different detector time resolution on photon detection ability are analyzed. The relationship between pulse arrival time and the similarity of pulse profile is established by numerical simulations. And the observations of the crab pulsar of hard X-ray modulation telescope is processed, the pulse profile characteristics of the Crab pulsar at different energy are studied. Secondly, the testing and processing methods of X-ray detector for pulsar navigation are studied systematically, and the testing work of a self-developed focused X-ray detector is completed by using the ground testing system. The test results show that the background noise of the focused detector is 3.63×10-5ph/(cm2·s-1), the working energy range is 0.2~22.7 keV, the time resolution is 4.17 μs, and the spatial response is about 5'. The energy linearity of the detector is good, the integral nonlinearity is 0.52%. The energy resolution of the detector is better than 200 eV at five characteristic energy spectra, and the best detection efficiency is 39.18%@4.51 keV. Under the condition of weak pulse signal and strong background noise, the detector can accurately restore the pulse profile of Crab pulsar. The signal-to-noise ratio and similarity of the pulse profile increase with the increase of pulse flow and the decrease of background noise. The detector can detect the pulse signal whose radiation flux is 10 times less than the background noise in 2 400 s. The results show that the focused detector has excellent performance and can meet the space observation requirements of navigation pulsars(eg. PSR B1509), so the feasibility of the testing method is also verified.
Acta Photonica Sinica
  • Publication Date: Jun. 25, 2020
  • Vol. 49 Issue 6 0604001 (2020)
Preparation and Optimization of Photosensitive Gate GaN-based High Electron Mobility Transistor Devices
ZHU Yan-xu, ZHU Yan-xu, YANG Zhuang, SONG Hui-hui, LI Lai-long, YANG Zhong, LI Qi-xuan, and HU Tie-fan
Based on the gate controlled characteristics of GaN High Electron Mobility Transistors(HEMTs) and on the photovoltaic effect in lead zirconate-titanate(PZT) ferroelectric thin films, a new type of photosensitive layer/HEMT detector structure is proposed. For this purpose, a PZT ferroelectric thin film is deposited on the gate of a HEMT device to prepare films with optimized photovoltaic performance, the surface morphology and ferroelectric properties of PZT films prepared by different sputtering powers and annealing temperatures are analyzed. It is found that the best conditions for the grain growth on the surface of the film are at 200 W sputtering power and 700℃ annealing temperature, and the residual polarization intensity is 38.0 μC·cm-2.The output characteristics of the fabricated photosensitive gate PZT/GaN-based HEMT devices are compared to those of pristine HEMTs under both dark condition and 365 nm ultraviolet light. The results show that the source drain saturation voltage of the HEMT with the ferroelectric thin film decreases by 3.55 V and the saturation current increases by 5.84 mA, compared with those without light, clearly indicating a significant UV photodetection capability. To achieve the purpose of optimizing the structure of the new type of detector, detectors with different grid lengths such as 1 μm, 2 μm, and 3 μm are tested. The results show that under ultraviolet light, the drain saturation currents of the three detectors are 23 mA, 20 mA, and 17 mA, respectively. Therefore, the longer the gate length, the smaller the saturation current of the device, and the worse the detection performance.
Acta Photonica Sinica
  • Publication Date: Jun. 25, 2020
  • Vol. 49 Issue 6 0604002 (2020)
Influence of Microchannel Plate Structure Parameters on Noise Factor
LI Xiaofeng, ZHANG Zhengjun, CONG Xiaoqing, FENG Hui, QIAN Yaohong, and LI Jiaojiao
The influences of structure parameters of microchannel plate, such as opening area ratio, thickness, electrode depth, ion barrier film and input enhancement film on noise factor, were studied by comparative measurement method. The results show that the noise factor decreases with the raising of opening area ratio; increases with the raising of thickness; increases with the raising of input electrode depth; increases by ion barrier membrane; decreases by the input enhancement film. The influence of ion barrier film on noise factor is the most, and the influence of thickness on noise factor is the least. The structure parameters of microchannel plate not only affect the noise factor, but also affect other parameters such as gain and uniformity. In order to reduce the noise factor of microchannel plate, the most feasible method is to increase the opening area ratio to 68 %, and then make a layer of MgO2 on the input end of microchannel plate. This will reduce the noise factor of microchannel plate close to 1 behaved in the ideal microchannel plate.
Acta Photonica Sinica
  • Publication Date: Apr. 25, 2021
  • Vol. 50 Issue 4 135 (2021)
Spatio-temporal Resolution Studies on a Synchronous Streak Tube
TIAN Liping, SHEN Lingbin, CHEN Lin, LI Lili, CHEN Ping, and TIAN Jinshou
A synchronous streak tube capable of providing high spatial resolution, high temporal resolution and large working area is numerically designed and experimentally demonstrated. In this paper, a 3-D model developed to systematically and comprehensively analyze the dependence of the physical temporal resolution on the accelerating voltage, the spatial resolution on the deflector-to-cathode distance, the dynamic spatial resolution and temporal resolution on the scanning velocity. Finally, geometry and electric parameters of dDC=100 mm, Ug=700 V, and Tscreen= 0.5 ns are proposed to optimize the streak tube performances. The numerical simulations show that the static spatial resolution is higher than 25 lp/mm @ MTF=10% and the dynamic spatial resolution is higher than 16 lp/mm @ MTF=10% over the whole effective photocathode area of 18 mm×2 mm. And, the simulated temporal resolution is better than 5.6 ps at Tscreen=0.5 ns. Furthermore, the photocathode radiant sensitivity can reach 51 mA/W at the wavelength of 400 nm. The tested static spatial resolution is as high as 25 lp/mm @ CTF=13%.
Acta Photonica Sinica
  • Publication Date: Apr. 25, 2021
  • Vol. 50 Issue 4 143 (2021)
Preparation and Performance Study of g-C3N4/CdS Heterojunction Ultraviolet-visible Photodetector
ZHI Pengwei, RONG Ping, REN Shuai, LIU Xiangwei, and GAO Shiyong
The g-C3N4 nanosheets are prepared by thermal polymerization method using melamine as the raw material. Then CdS nanoparticles are grew by the chemical bath deposition, which in turn construct the g-C3N4/CdS heterostructures successfully. The scanning electron microscope, X-ray diffractometer and X-ray photoelectron spectroscopy are applied to characterize the morphology, crystal structure and chemical composition of samples. It is shown that the CdS nanoparticles with hexagonal wurtzite structure are uniformly attached to the surface of g-C3N4 nanosheets. The g-C3N4/CdS photodetector has a better photoresponse to ultraviolet light at zero bias voltage, and its photocurrent value is about 8 times higher than that of the g-C3N4 nanosheet photodetector. Moreover, the g-C3N4/CdS photodetector also displays well light response in the visible light region, and shows stability and cyclicity of detection to blue and green light.
Acta Photonica Sinica
  • Publication Date: Sep. 25, 2021
  • Vol. 50 Issue 9 0904001 (2021)
Multistage Photosynaptic Transistor Based on the Regulation of Ferroelectric P(VDF-TrFE)
HE Lihua, LI Enlong, YU Rengjian, CHEN Huipeng, and ZHANG Guocheng
The persistent photoconductivity of organic material PDVT-10 combined with the polarization field provided by ferroelectric material P(VDF-TrFE), was used to control the relaxation characteristics of the photosynaptic device by adjusting the polarization intensity of ferroelectric material. The basic functions such as short-term plasticity and paired pulse facilitation of synapses are simulated, and the multilevel dimmable optical synapses are further realized. Moreover, the relaxation phenomenon of continuous photoconductance effect is similar to the flow characteristics of Ca2+ in biological synapses, which can better simulate the synaptic behavior of biological synapses. This study provides a new idea for the development of adjustable photosynapses.
Acta Photonica Sinica
  • Publication Date: Sep. 25, 2021
  • Vol. 50 Issue 9 0904002 (2021)
Comparison of Resolution Between Super Gen.Ⅱ and Gen.Ⅲ Image Intensifier
LI Xiaofeng, CHANG Le, ZHAO Heng, QIU Yongsheng, CHEN Junyu, and ZHANG Yanyun
In this paper, the resolution of the super second generation image intensifier and the third generation image intensifier under different illuminations are studied. The results show that the resolution of the super second generation image intensifier and the third generation image intensifier with the same gain, limit resolution, signal to noise ratio and modulation transfer function is constant when the input illumination is above 4.3×10-3 lx, and does not change with the change of input illumination The resolution of the super second generation image intensifier is lower than that of the third generation image intensifier. The lower the input illumination, the greater the difference. The reason is that the third generation image intensifier has higher cathode sensitivity. The higher the sensitivity of the cathode, the higher the initial contrast of the photocathode, and the higher the contrast of the target image on the fluorescent screen, so the higher the resolution under low input illumination. Figure of Merit is an index to characterize the comprehensive performance of image intensifiers. However, when Figure of Merit is used to compare the comprehensive performance of image intensifiers, it can only be compared between the image intensifiers with the same photocathode, but not between the image intensifiers with different photocathode. Therefore, the Figure of Merit can not be used to compare the performance of super second generation and the third generation image intensifiers.
Acta Photonica Sinica
  • Publication Date: Sep. 25, 2021
  • Vol. 50 Issue 9 0904003 (2021)
Preparation of 2D Composite Grating Antireflection Coatings and Its Application in Solar Cells
ZHOU Bochuan, FANG Chaolong, and ZHANG Yaoju
A Two-dimensional (2D) composite grating is proposed to reduce the reflection of the interface of the epoxy-resin-encapsulated silicon solar cell and improve its photoelectric conversion efficiency. The 2D composite grating is prepared by longitudinally stretching One-dimensional (1D) Polydimethylsiloxane (PDMS) grating together with plasma surface modification. Scanning Electron Microscope (SEM) characterization of the 2D composite grating shows that nanowrinkles are longitudinally and orderly distributed on the surface of 1D grating. Optical measurement and theoretical simulation consistently demonstrate the 2D composite grating has superior antireflective property to 1D grating. Electrical characterization shows adding the 2D composite grating onto the epoxy-resin-encapsulated Si solar cell as an antireflective coating can improve the photoelectrical conversion efficiency, reduce the adhesion of dust particles and enhance the surface hydrophobicity and the self-cleaning property of Si solar cell.
Acta Photonica Sinica
  • Publication Date: Sep. 25, 2021
  • Vol. 50 Issue 9 0904004 (2021)