基于碲化锌晶体光学整流及电光采样的太赫兹时域光谱系统

发布时间：2018-12-13 03:03

【摘要】：太赫兹波是指频率介于0.1THz-10THz(1THz=1012Hz)的电磁辐射。有报道显示大量半导体的子带和微带能量都处于太赫兹范围,众多生物大分子的共振和转动能级跃迁频率也都在太赫兹频段内有所分布,因此太赫兹辐射具有独特的光谱分辨能力。而且太赫兹辐射光子能量小,不会对物质造成结构性损害,基于以上特点,以太赫兹辐射为基础的太赫兹时域光谱技术作为一门新兴的检测技术在物质分辨方面有着优异的表现,在生物医学、安全检查、文物鉴定等领域有着广阔的应用前景。本文研究的是基于碲化锌晶体光学整流和电光采样的太赫兹时域光谱系统,文章的主要内容安排如下。第一章,研究背景介绍及国内外研究概述。简要说明“太赫兹间隙”的位置及来由,简单介绍国内外太赫兹研究风潮以及太赫兹辐射的独特性质及应用。第二章,太赫兹的产生方法及激发源。根据激发方式的不同,将涉及的产生方法分为光子学和电子学两大类分别介绍。第三章,时域光谱系统原理的介绍。首先从麦克斯韦方程组出发得出光致极化过程中辐射的电磁脉冲远场解,由其来推演在碲化锌晶体光学整流中辐射电磁脉冲的电场形式。然后对非线性晶体中的线性光电效应进行深入的分析,此效应被用在碲化锌晶体中的电光采样探测中。第四章,实验数据分析。首先介绍一下太赫兹时域光谱系统的光路设计,然后通过时域光谱系统对水蒸气在太赫兹波段内的吸收进行探究。接下来测量咖啡等有机饮品的透射谱线,分析谱线得到的结果。测量硅片及硅片衬底ITO薄膜的透射谱,所测结果与理论模拟结果吻合良好。最后,对硅衬底纳米薄膜在各特殊角的情形下获得的特殊性质进行了理论模拟。
[Abstract]:Terahertz waves are electromagnetic radiation with a frequency of between 0.1THz-10THz (1THz=1012Hz). It has been reported that a large number of semiconductor subbands and microstrip energies are in the terahertz range, and the resonant and rotational energy transition frequencies of many biological macromolecules are also distributed in the terahertz band. Thus terahertz radiation has a unique spectral resolution. And because terahertz radiation photons are small in energy and do not cause structural damage to matter, based on these characteristics, Terahertz time-domain spectroscopy based on terahertz radiation has excellent performance in matter resolution as a new detection technology. It has a broad application prospect in biomedicine, safety inspection, cultural relic identification and so on. The terahertz time-domain spectroscopy system based on optical rectification and electro-optic sampling of zinc telluride crystal is studied in this paper. The main contents of this paper are as follows. The first chapter, the research background and domestic and foreign research overview. This paper briefly describes the position and reason of "terahertz gap", and briefly introduces the unique properties and applications of terahertz research and terahertz radiation at home and abroad. The second chapter, the generation method and excitation source of terahertz. According to the different modes of excitation, the methods involved are divided into photonics and electronics. Chapter three introduces the principle of time domain spectrum system. The far-field solution of electromagnetic pulse radiation in the process of photopolarization is obtained from Maxwell's equations, from which the electric field form of radiated electromagnetic pulse in optical rectifier of zinc telluride crystal is deduced. Then the linear photoelectric effect in the nonlinear crystal is analyzed, which is used in the electrooptic sampling detection of zinc telluride crystal. Chapter four, experimental data analysis. The optical path design of terahertz time-domain spectrum system is introduced, and then the absorption of water vapor in terahertz band is studied by time-domain spectroscopy system. Then the transmission lines of organic drinks such as coffee were measured and the results were analyzed. The transmission spectra of ITO films on silicon substrates and on silicon substrates are measured and the results are in good agreement with the theoretical simulation results. Finally, the special properties of silicon substrate nanocrystalline films at different angles are theoretically simulated.
【学位授予单位】：苏州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN304.22

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