Study Of Irradiation Effect To PV HgCdTe Linear Array Detector By Fs Laser

HgCdTe detector is widely used in civilian and military domain. Femto-second (fs) laser's features of high peak power and short operative time make it different from the continuous wave (CW) laser in destructive mechanics and destructive effect. The comparative study of irradiation effect on HgCdTe detector by fs laser and CW laser is significant.The different irradiation effect on the HgCdTe detector by fs laser and CW laser is studied, and some experimental research of irradiation effect on a PV HgCdTe linear array detector with 256 elements was made.1.The irradiation effect on the detector by 1319nm CW laser was studied, and the phenomena of the detector's saturation dip and the raise of saturation dip are observed in the experiments. The saturation threshold of the detector element is between 6.4×10-3W/cm2 and 7.3×10-3W/cm2, the saturation dip threshold is below 0.63W/cm2, and the raise of saturation dip threshold is between 21.9W/cm2 and 42.3W/cm2. It can be analyzed from the experiment that the relation of the number of the detector's saturated element and the laser power density is linear when the power density is between 1.2×10-2W/cm2 and 0.40W/cm2; the detector doesn't have irreparable damage or reparable damage by 1319 nm CW laser at the average power density below 845W/cm2.2.The irradiation effect on the detector by 1030nm and 800nm fs laser is studied, and the saturation thresholds of the detector element are between 6.5×10-4W/cm2 and 9.3×10-4W/cm2 at 1030nm, and between 8.9×10-5W/cm2 and 5.8×10-4W/cm2 at 800nm. The 800nm laser's reparability damage threshold is 1.12×10-2J/cm2 and irreparability damage threshold is 0.19J/cm2. The experiments'results indicate that the single pulse energy density of fs laser is the main factor to make detector's saturation, reparable damage and irreparability damage. The phenomena of the flat-output region, the flat out-put cycle,and the residual signal is observed in the experiments. The flat-output region threshold is between 6.5×10-4J/cm2 and 9.3×10-4J/cm2 at 1030nm, and is between 5.4×10-4J/cm2 and 5.8×10-4J/cm2 at 800nm; the 800nm laser's flat out-put cycle threshold is between 2.3×10-4J/cm2 and 2.4×10-4J/cm2; and the 800nm laser's signal remainder threshold is between 5.5×10-4J/cm2 and 7.4×10-4J/cm2. The phenomena of extraordinary corresponding and suppression of damaged element is found in the experiments.3.The conclusion is achieved that fs laser is better than CW laser by comparing the detector's damage effect by fs laser and CW laser's irritation: the detector does not have been damaged by CW laser, while fs laser can damage the detector at the same average power density.