基于双光频梳多外差干涉和飞行时间法的高精度气体吸收光谱探测

项目名称： 基于双光频梳多外差干涉和飞行时间法的高精度气体吸收光谱探测

项目编号： No.61205147

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 信息四处

项目作者： 尉昊赟

作者单位： 清华大学

项目金额： 29万元

中文摘要： 具备高光谱分辨率、高信噪比、高精度光谱位置及高精度吸收光程测量能力的高精度气体吸收光谱探测系统在光谱数据库构建、痕量气体定量分析等方面具有重要的应用价值, 但技术实现极富挑战性。本申请提出一种基于双光频梳的气体吸收光谱探测原理和方法。该方法的核心是双光频梳，通过对其参量的控制，实现光谱分析所需的吸收光谱和吸收光程的高精度测量。将双光频梳配置成具有一定重复频率差异的光源，实现多外差干涉机理的光谱探测。对光频梳参量进行优化，并有效锁定和精确测量，可提高信噪比和光谱位置精度。将双光频梳配置成同参量同步扫描的光源，实现基于飞行时间法的吸收光程测量，并采用相移算法提高测量精度。本申请将构建一套实验系统，实现光谱分辨率0.01波数，光谱带宽800波数 (6050波数~6850波数)，信噪比>1000:1，光谱位置不确定度1E-6波数，吸收光程测量相对不确定度5E-5的高精度光谱探测。

中文关键词： 双光梳光谱；多外差干涉；非线性异步光学采样；混合锁模；蒙特卡洛方法

英文摘要： High precision gas absorption spectra measurement, with high performances of spectral resolution, signal to noise ratio (SNR), spectral line position accuracy, and absorption length accuracy, is a powerful tools in developing of high resolution transmission database and quantitative analysis of trace gas. However it is not easy to achieve. To meet the challenge, we propose a new gas absorption spectra measurement method using dual optical frequency combs (OFCs). With the proposed method, the spectrum and absorption length can be measured precisely via locking the repetition rates and the offset frequencies of the two OFCs with different values. When the repetition rates of the two OFCs are set with a tiny difference, the dual OFCs create a multi-heterodyne spectra measurement system. The SNR and the spectral line position accuracy can be improved by optimizing the repetition rates and the offset frequencies, and then lock and measur these parameters precisely. While the repetition rates and the offset frequencies of the two OFCs are configured identically, the absolute absorption length can be measured using the time-of-flight method by scanning the repetition rates of the two OFCs synchronously. A phase-shifting algorithm, calculating the pahse envelope from the interferometry, is also used to determine the abs

英文关键词： dual-OFC spectrum；multi-heterodyne interferometry；non-linear ASOPS；hybrid mode-locked；Monte Carlo method