LiNbO_3:Fe晶体的光致声发射现象

Light induced acoustic effect in LiNbO_3:Fe crystals

本文观察到了LiNbO_3:Fe晶体在光致准击穿时的一种声发射现象,产生的低频声波调制了输入晶体的超高频声信号。其频率随入射光强辐照时间增加而增大,其周期与同时测量的光生伏特电流、光致折射率变化以及某一点衍射光强的跃变周期相同。文中对比现象作了,探讨认为它起因于准击穿时跃变空间电荷场的逆压电效应。

The phenomena of acoustic emission in LN:Fe crystals nave been observed during the process of light induced quasi-breakdown. It is found that the super high frequency acoustic signal has been modulated by the low frequency acoustic wave which was introduced into the crystals, the frequency of which increases with the increasing of intensity of incident light and the period of the breakdown is the same as the jump one of the photovoltaic current and the light induced change of refractive index. It is caused by the strain effect of crystal induced from jumped space change field.