中文摘要：

研究了带偏置电压的向列相液晶盒结构中在激光脉冲作用下的分子转动动力学模型。结果表明，入射光脉冲的宽度远大于1 ps时，光脉冲诱导液晶分子重取向过程可用德拜弛豫过程描述。弛豫时间常数与液晶盒厚度的平方成正比，和液晶的弹性常数成反正。弛豫时间常数依赖于液晶横向位置，预偏角的范围在0~0.4 rad之间变化时，不同位置的时间常数相差较大，可在一个量级之间变化；预偏角在0.4~π/2 rad时，时间常数基本不变。弛豫时间常数还受偏置电压控制，1.2~10 V偏置电压时液晶盒中心处的弛豫时间常数在10 ms~10 s变化，变化范围可达3个数量级。

英文摘要：

The molecular reorientation transient process induced by laser pulse in nematic liquid crystals （NLC） with bias voltage is explored. The results show that if the width of pulse is large more than 1 ps, the molecular reorientation transient process induced by the pulse can be modeled as Debye relaxation process, the relaxation time constant is inversely proportional to the elasticity constant of NLC, and is proportional to the square of thick of the cell. On one hand, the relaxation time constant is transversely dependent, for the pretilted angle varied in 0~0.4 rad, the relaxation time constant can be varied in one order of magnitude, for the case of pretilted angle is more than 0.4 rad, the time constant remains the same. On the other hand, the relaxation time constant can be steered by bias voltage, reorientation relaxation time ranges from 10 ms~10 s can be obtained if the 1.2~10 V bias voltage is applied to the cell.