Researches On The Abnormal Response Of PV-HgCdTe Linear Array Detector Induced By Short Pulse Laser

The infrared detectors have been widely used in the fields of military,industrial and aerospace,and more and more attention has been paid to the research of HgCdTe detectors and the effects of laser irradiation.Researchers at home and abroad have carried out a large number of jobs.The development of ultrashort and ultrafast pulsed lasers has provided an opportunity for the study of the irradiated effects of HgCdTe detectors,and in extreme light conditions we have found some new responses to the HgCdTe detectors,such as the overall jump of the base signal Zero pressure output,abnormal response of optical response signal,and abnormal response of damaged unit.In this paper,the response law and mechanism of HgCdTe infrared detectors under short pulse and extreme light conditions are studied.In addition,the noise enhancement effect in the pulse laser irradiation experiment and the laser response characteristics inside and outside the detector time are studied in order to help improve the understanding of the intrinsic characteristics of the HgCdTe materials and devices,and improve the device The performance and processing technology to provide a reference.The main research work is as follows:1.In the short pulse laser irradiation experiment found the detector base signal overall jump zero pressure output phenomenon,that is,the base signal response V1 of the irradiated pixel with the increase in laser power density response saturation,zero pressure Output the two-phase response rule.Unlike in the past the zero-voltage output phenomenon discussed in this paper the zero-voltage output of base signals V1 is all the pixel and is a transition,not a continuous buck.By analyzing the structure of the detector readout circuit,it is considered that the voltage Vb of the common P pole inside the photodiode increases instantaneously with the increase of the laser energy,and the output voltage of all the units decreases,that is,the potential difference between the two ends of the integrating capacitor decreases So that the base signal V1 as a whole jumped to about OV,the base signal as a whole of the zero-voltage output phenomenon.2.In the nanosecond pulsed laser irradiation experiments,sag output-recovery-convex of photoresponsive signal have been discovered.Through theoretical analysis,it is concluded that the main reason for the output of the photoresponsive signal is that the Vb increases instantaneously with the increase of the laser energy,the operating condition of photodiode is changed from zero bias to positive bias,and the output voltage decreases.At the same time,with laser energy density increasing,the reset voltage of the irradisted part enlarged,while the counterpart of the unirradiated part stays the same,which is the dominating factor resulting in the sag of the optical signal.Further study about the sag recovery and sag convex of the optical signal will be carried out to explain these phenomena.3.The experiment found that when the laser energy is too strong lead to photoreceptor damage,the damaged unit in the absence of light there is a spike output voltage,and the response voltage amplitude changes with time.4.The response characteristics of the short pulse laser irradiation in inside and outside of the detector integral time are studied experimentally,and the mechanism of different response phenomena is analyzed according to the signal readout principle.5.The experimental results show that the The short pulse laser leads to the phenomenon of noise enhancement in HgCdTe detector,and the source and induction way of the noise enhancement effect are studied in detail by contrasting experiment,and some suggestions for suppressing the noise enhancement effect are given.