Invited paper- Laser irradiation effect of photoelectric device
2017, 46(10): 1003001.
doi: 10.3788/IRLA201746.1003001
By the way of 1-on-1, the FT50M FT-CCD working on the evaluation kit is irradiated by the 1 064 nm pulse laser with 8 ns pulse width. The experiment shows that, along with the increase of laser pulse energy density, the damage phenomena of unilateral black line, white spot and bilateral white line from the position irradiated by laser successively appear in the output image of FT-CCD. This process distinguishes obviously from the IT-CCD, which presents successively the white spot and bilateral white line in the similar experiments. Comparing the structures of FT-CCD and IT-CCD, and combing the damage mechanism of IT-CCD, it is thought that the first occurrence of unilateral black line damage phenomenon indicate a FT-CCD damage mode of the poly-silicon electrode being damaged earlier than the Si substrate. This study enriches the knowledge of laser damaging CCD image sensor, and provides a new clue for deep searching the mechanism of laser damage CCD.
2017, 46(10): 1003002.
doi: 10.3788/IRLA201747.1003002
Experimental research on pulsed nanosecond laser irradiation on Charged Coupled Devie was carried out to understand the damage and blindness mechanism of multiple pulses interaction with EO systems. The results showed two distinctive damage effects and mechanisms. It exhibited damage and blindness accumulation effects and damage threshold reducing outcomes with multiple pulses arriving at the same spot on CCD, including point-to-line damage and line-to-full frame blindness. The threshold reducing outcomes is closely related with pulse number and laser fluence with the same mechanism as single short blindness. However, the damage mechanism for multiple-pulse damage to different pixels is obviously different, which attributes to a multiple vertical line damage superposed effect without electrical disorder. The functional blindness threshold is indentified with line damage threshold 660 mJ/cm2, and evidently less than that of single-pulse blindness threshold 1 500-2 200 mJ/cm2.
2017, 46(10): 1003003.
doi: 10.3788/IRLA201748.1003003
The response law of output signal for irradiated and unirradiated pixel in PV-type HgCdTe linear array infrared detector was researched when energy density of nanosecond pulse laser, less than destroyed threshold, was increased. The features of two-stage response of base signal and six-stage response of optical signal were pointed out, the energy density threshold range of each response phase was also given; some abnormal response phenomena such as zero voltage output of base signal integral jumping, sag output-recovery-convex of optical response signal were discovered. Based on the above results, from the point of view of readout circuit and thermo-induced electrodynamic force, the mechanism of abnormal response was revealed. We hope to strengthen the deep understanding of the photoresponse characteristics of HgCdTe array infrared detector, and provide inspiration for the technical innovation of this kind of device.
2017, 46(10): 1003004.
doi: 10.3788/IRLA201749.1003004
The multi-group circular fringes on the optoelectric detector were observed in the experiment of laser disturbing optoelectric imaging systems. The method of disassembly, measurement, modeling and ray tracing of optical system was used to investigate the formation mechanism of multi-group circular fringes. First of all, the radius of curvature, thickness, pupil of every lens were measured and the model of optical system in TRACEPRO software was built. Based on the model, large number of random rays to propagate in the optical system were traced secondly and the energy distribution on the optoelectric detector was obtained. By analyzing the origin of every energy component, it was found out that the multi-group circular fringes were caused by interference effect of the different energy component on the optoelectric detector. The research results can provide the technical support for evaluating laser disturbing effect on optoelectric imaging systems.
2017, 46(10): 1003005.
doi: 10.3788/IRLA201750.1003005
To study the influence of laser radiation on the performance of an image intensifier, the irradiation experiment of CW laser on the image intensifier was carried out and the effect of laser irradiation on its gain characteristics was analyzed. Experimental results show that no pixel crosstalk phenomenon is found as the increase of the laser power until the light illumination arrives 8104 times of the illumination for point saturation, meaning that the gain of the image intensifier is saturated and the output light intensity of image intensifier will not increase indefinitely. The equivalent circuit model of the microchannel plate of the image intensifier was established and its gain characteristic was analyzed. The maximum current for linear gain, got from this model, was approximately 1.6410-10 A, which was very close to experimental data, indicating that the charge extracted from the microchannel wall cannot be replenished in time is the main reason of gain saturation.
2017, 46(10): 1003006.
doi: 10.3788/IRLA201751.1003006
In order to study the effects of single-junction GaAs photovoltaic cell irradiated by 808 nm continuous wave laser, a physical model was established by software COMSOL and MATLAB. The voltage-current characteristics, open circuit voltage, short circuit current, photoelectric conversion efficiency, fill factor and heat steady temperature of cell were simulated, and the influence of the power densities, equivalent series, parallel resistance and antireflection coating were also discussed. The results shows that open circuit voltage and short circuit current increases with the increase of laser power density, while conversion efficiency and fill factor have maximum value. Reducing equivalent series resistance and increasing equivalent parallel resistance are an effective method to improve the output performance of cell. It was significant to improve the efficiency of cell with adding antireflection coating, however making the cell temperature higher at heat steady. The conversion efficiency of cell reaches to maximum value of 50.13% under 62.4 mW/cm2 at heat steady. The simulation result is basically consistent with relevant experiments, which can provide theoretical reference for output characteristics study of photovoltaic cell by continuous wave laser irradiation at some extent.
