设计了一种环带阶梯形光栅限幅器,理论推导并数值模拟了光束通过该限幅器后在限幅光阑平面上的光场分布,定量分析了光强分布随光栅参数的变化规律。结果表明:环带阶梯型光栅实际上是一种闪耀光栅,选择合适的结构参量,可使能量集中分布在偏离光阑中心较远且宽度较大的圆形环带上;亮环位置由光栅递增厚度、光栅周期等参量确定;衍射最亮环位置随光栅递增厚度的增加周期性改变,当递增厚度满足一定条件时,最亮环位置与入射激光波长无关,这对设计多波段的光限幅器比较有利。

An optical limiter has been designed based on the step ring grating.The intensity distribution of a beam transmitting through the limiter was derived theoretically and simulated,and the changes rules of intensity distribution with grating indexes were analyzed in numerical methods.The simulation results show that this grating is a kind of blazed grating,and the incident energy would mainly distribute on one or two wide light rings apart from the aperture center for the limiter with suitable indexes.The light ring position is determined by grating depth step and period.It changes in period when the depth step increases,and the lightest ring position is independent of incident wavelengths if suitable indexes are selected,which is useful for designing effective multiband limiters.