电磁诱导透明效应增强的四波混频光谱技术用于锂同位素高分辨痕量测量

项目名称： 电磁诱导透明效应增强的四波混频光谱技术用于锂同位素高分辨痕量测量

项目编号： No.61475125

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 无线电电子学、电信技术

项目作者： 陈浩伟

作者单位： 西北大学

项目金额： 85万元

中文摘要： 锂(Li)同位素比值法在地表风化等地球环境科学研究中有着重要的应用。质谱法是目前Li同位素测量的主要手段，但这种方法的样品预处理过程（分离、提纯、富集）复杂，会造成样品浪费、分析速度慢、效率低等。光谱法的样品预处理过程简单，但目前的光谱技术不能有效分辨Li-7的D1线和Li-6的D2线。鉴于此，本项目提出利用电磁诱导透明效应（EIT）增强的四波混频（FWM）光谱技术来测量Li同位素并研究相关的物理问题：研究EIT效应对FWM信号的增强机制；理论推导FWM信号强度与样品浓度之间的量化关系，结合实验研究影响该量化关系的因素；实现地球环境样品（岩石、土壤、水体等）中的Li同位素的高精度测量，为地表风化研究提供定量的依据。该技术的优势在于：分辨率高，可消除多普勒展宽，且能避免Li-7对Li-6的干扰；灵敏度高，无需样品富集过程。为此，本项目的开展将为地球环境科学领域提供一种新的研究手段。

中文关键词： 锂同位素；电磁诱导透明；四波混频；痕量测量；地表风化

英文摘要： Lithium (Li) isotopic ratio method has an important application in the study of Earth & Environmental Science, such as surface weathering investigation, etc. Nowdyas, mass-spectroscopy is the main method used in Li isotope measurement. However, the sample pretreatment processe of this method is quite complicated and time-consuming, including separation, purification and enrichment processes. These processes can cause sample waste, analysis speed slow and efficiency low, etc. The sample pretreatment process of spectrometry is simple. But the current spectroscopic techniques cannot distinguish the Li-7 D1 line and Li - 6 D2 line effectively. In view of this, we propose to measure Li isotopes by electromagnetically induced transparency (EIT) enhanced four-wave mixing (FWM) spectrometry and study the relevant physics problems: invstigating enhancement mechanism of EIT on FWM signal intensity, deducing the relationship between the content of Li isotopes in the analytes and FWM signal intensity, studying on the influence factors of the relationship according to the experiment, measuring the Li isotopes contents in the earth and environmental samples (rock, soil and water, etc) and providing a quantitative basis for the study of earth and environmental science. There are two main advantages of this technique. One is high resolution. It is a Doppler-free method and can avoid the interference between Li-7 and Li-6. The other one is high sensitivity. So it does not need a sample enrichment process. This project is to explore a new method for the study of Earth & Environmental Science.

英文关键词： Lithium isotope;Electromagnetically induced transparency(EIT);Degenerate four-wave mixing;Trace measurement;Surface weathering