中文摘要：

以返波振荡器作为太赫兹波辐射源,搭建了一个基于Fabry-Perot干涉原理的光学材料参数测量系统.利用返波振荡器的可调谐特性,测量了样品的透射谱,并提出了精确提取材料光学参数的方案.该方案包括：基于模拟退火的光学材料介质常数寻优算法,针对样品厚度误差的厚度优化方法以及根据测量系统特点设计的峰谷权值优化.并以半导体砷化镓（GaAs）样品的光学材料参数测量为例,验证了材料光学参数提取方案的有效性.

英文摘要：

A THz spectral measurement system based on Fabry-Perot effect is built up to extract optical material parameters by using a backward-wave oscillator （BWO）.As a coherent,continuously frequency-tunable radiation source,backward-wave oscillator can be used to measure samples＇ transmission spectrum.To enhance the accuracy of the optical parameters,Simulated Annealing Method to optical material dielectric constant extraction and define error function is applied to describe the fit result.As uncertainty of sample thickness may lead to inaccurate results,accurate determination of the sample thickness is used.And,after considering the measurement system＇s own principle and characteristic,knowledge of weight distribution is designed which can further enhances the accuracy of optical material parameters.These techniques are experimentally verified using a 900 μm-thick GaAs sample.