平面变间距光栅的夫琅禾费衍射场分析

采用对单缝衍射结果进行直接叠加和根据标量衍射理论进行严格积分的两种方法进行推导,分析平面变间距光栅的夫琅禾费衍射场光强分布.在光栅各周期狭缝宽度δ0相差不大时两种方法得到的光强分布差异不大;但当δ0变化较大时,虽然零级衍射中心重合,但是在其他级次,如一级衍射极大的光强在峰值大小和位置上都表现出明显的差异.文中还通过变间距光栅的实例和matlab数值模拟进行分析,根据标量衍射理论通过严格积分将能给出更为普适的结果.在此基础上,联系平面变间距光栅夫琅禾费衍射场的光强分布,对这类光栅的位移传感和自聚焦特性做了介绍.

Analysis of Fraunhofer Diffraction Field Distribution for One Dimensional Variable-Line Space Gratings

Two methods were proposed to deduce the distribution of the Fraunhofer diffraction field for one dimensional Variable-Line Space gratings（VLS gratings）,including surposing the complex amplitude of the diffracted light by a narrow slit and strict integration of illustrating area of grating depended on the scalar theory.It shows that both calculating results are nearly the same when the grating has similar slit widths of different periods.But when the VLS grating has variable slit widths,it represents obviously difference with the position and intensity of higher diffraction orders except the zero order.Examples are taken to analyze the distribution of diffraction field of VLS grating,which are also discussed by simulating with Matlab software.From the preceding discussion we can immediately draw a conclusion that strict integration depended on the scalar theory is more suitable for VLS grating to investigate its diffraction field distribution.Moreover,brief introduction was given about the ability of VLS gratings for displacement sensor and focusing wave,basing on the above analysis.