改进的液晶可调谐滤光片设计方法

Improved design method of liquid crystal-based tunable filter

为了实现程序可调的可见光谱连续可调滤光,对多级液晶(LC)可调谐滤光片的设计方法进行改进,并对设计结果进行软件模拟与实验.改进后的设计方法是通过分析每一级滤光片需要的双折射光程差以及液晶盒的双折射光程差调节能力,从而确定各级滤光片所采用的石英片与液晶盒的参数.使用这种方法设计了6级可调谐滤光片并进行模拟分析,模拟结果证明,该滤光片系统可以在400～700nm波段进行调谐,通带半高宽(FWHM)最小可达8nm,实现了宽谱段窄带滤光.实际制作了6级液晶可调谐滤光片,对滤光片进行了测试,测试结果表明性能指标达到了设计要求.

The design method of liquid crystal （LC）-based filter was improved to accomplish program-controlling tunable filter with continuous tuning ability in visible spectrum range.Software simulation and relative experiments of design results were conducted.The parameters of the quartz plates and LC cells in every stage of the filter system were decided by analyzing the birefringence path difference required by every stage and the tunable birefringence path difference provided by LC cell.A six-stage tunable filter system was designed.Simulation results proved the visible spectrum tuning ability of the filter system.Full width at half maximum （FWHM） can be at least 8 nm and narrow-band filtering can be achieved in a wide spectrum range from 440 nm to 700 nm.Six stages of the filter system were assembled and tested.Results show that the main performance index can be achieved.