基于非线性激光差频理论与光腔衰荡技术痕量气体分子浓度测量和组分分析的研究

项目名称： 基于非线性激光差频理论与光腔衰荡技术痕量气体分子浓度测量和组分分析的研究

项目编号： No.60877047

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 生物科学

项目作者： 李志全

作者单位： 燕山大学

项目金额： 30万元

中文摘要： 本项目提出了基于非线性光谱学、分析化学、激光技术等基础理论的连续波激光调制的痕量气体分子浓度测量的研究。项目重点研究大气、工业、生物医学等环境下痕量气体的吸收光谱特性；设计三重信号调制的气体浓度测量系统；研究光腔内激光信号衰减速率和气体分子浓度的数学关系，建立测量模型，避免了浮质散射、Rayleigh散射对测量结果的影响，这是一项突破性的工作；为解决可调谐激光器的调谐范围较窄的难题，利用PPLN晶体非线性差分激光生成器调制TDL激光器和Nd:YAG激光器，使得激光器的调谐范围提高了2个数量级。本项目研究成功进而得到应用可取得一种高精度痕量气体分子浓度测量和组分分析的有效方法，促进气体浓度测量仪器、光谱学、激光技术的应用；可推动材料学、薄膜技术、激光、光纤传感与通信等技术的发展。

中文关键词： 痕量气体浓度测量；三重信号调制；非线性激光差频；光腔衰荡

英文摘要： In this work, we proposed the investigation of trace gas concentration measurement using continuous wave laser modulation based on the theories of nonlinear spectroscopy, analytical chemistry and laser technique. The key research contents are as following: 1)the characteristics of absorption spectrum of trace gas in environments of atmosphere, industry and biomedicine, etc are researched; 2)the design of gas concentration measurement system modulated by ternary signal is proposed and the dependence of decay rate of laser signal in the cavity and gas molecules concentration is analyzed; 3) the measurement model is established to avoid the influence of scattering, such as Rayleigh, on results of measurement that of being groundbreaking work; 4) to solve the problem of narrow tunable range of tunable laser, nonlinear difference laser generation on the basis of PPLN crystal is utilized to modulate TDL laser and Nd: YAG laser, by which the tunable range is increased 2 orders of magnitude. The succeed of this work even application can obtain an effective method of measuring trace gas concentration in high precision and enhance the practical application of measurement instruments of gas concentration, spectroscopy and laser technique; in addition, it is able to promote the developments of materials, thin film, laser, optical fiber and communication.

英文关键词： Concentration measurement of trace gas; ternary signal modulation; nonlinear frequency difference of laser; ring-down