摘要:
由材料参数测试和器件响应率测试证实,LiNbO3晶体的热释电响应率优值Mv为一般公认值的二倍。而且当温度升高时,Mv缓慢降低,并不出现某些文献所预示的明显增加。着重研究了LiNbO3探测器在高功率密度连续激光辐照下的输出特性。研究结果表明,在相同条件下,LiNbO3探测器的输出开始偏离线性所对应的最大功率密度远高于LiTaO3。仔细测定了LiNbO3晶体的固有介质损耗,并据此估计LiNbO3器件探测率的极限值。分析表明,就制备背景限探测率的器件的潜力而言,LiNbO3不低于TGS。
Abstract:
Based on the experimental results obtained from both the measurement of material parameters and device responsivity, it is verified that the pyroeleetric responsivity figure of merit of LiNbO3 crystal, Mv is twice as high as that generaly acknowledged value. Furthermore, when the temperature rises, Mv slowly decreases rather than in-creases evidently with temperature as reported in certain literatures. In this paper, the output characteritics of LiNbO3 pyroeleetric detector which is irradiated by the high-power CW CO2 laser has been investigated. The results show that the maximum power density at which the output characteristics of LiNbO3 detector begin to deviate from linear range far exceeds that of LiTaO3 detector under the same conditions. We have carefully measured the intrinsic dielectric loss tgd of LiNbO3 crystal. The value obtained can be used to estimate the detectivity limit of LiNbO3 pyroelectric detector. Detailed analysis proves that, for producing the pyroelectric detector with background limited performance, its figure of merit of LiNbO3 crystal is favorable, and no loss than those of most commonly used materials, such as TGS.
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