双光束组合激光辐照光导型CdS光电探测器的实验研究

Photoconduction-Type CdS Detector Irradiated by Two Laser Beams

为研究波段内和波段外组合激光对光导型光电探测器的辐照效应,实验采用532nm(波段内)和1319nm(波段外)双光束组合连续激光辐照光导型CdS光电探测器,分别改变两束激光的辐照功率,得到探测器的电压响应曲线。实验结果表明,光电探测器对波段内和波段外激光都有响应,但在激光开始和停止辐照瞬间探测器对两束激光的响应电压刚好相反。探测器对波段外激光的电压响应随线性工作区间内的波段内激光功率升高而增大;随着波段内激光趋于饱和,对波段外激光的响应电压近似指数级下降。分析认为,光电探测器对波段外激光的响应为光激发热载流子效应,是由自由载流子吸收激光能量产生带内跃迁引起的;波段内激光辐照影响探测器对波段外激光的吸收系数。

PC-type CdS detector is irradiated by 532 nm in-band and 1319 nm out-of-band continuous wave （CW） lasers simultaneously. The voltage responses are recorded when the power of the two laser beams changes separately. It is shown that the detector responses to the irradiation of both in-band and out-of-band lasers, but the response to the irradiation of out-of-band laser is opposite to that of in-band laser. The voltage response to the out-ofband laser increases with the rise of line-working in-band laser power and decreases rapidly while the in-band laser power approaches to the saturation threshold. Analysis shows that the response to the out-of-band laser is related to laser excited hot carriers, which is due to the carrier absorption of the incident photons resulting in an intra-band transition. In-band laser irradiation has an effect on the absorption coefficient of the out-of-band laser.