基于光腔衰荡光谱测定玻尔兹曼常数

发布时间：2018-03-09 03:34

本文选题：温度　切入点：温标　出处：《中国科学技术大学》2017年博士论文　论文类型：学位论文

【摘要】：分子光谱是研究分子结构、内部能量布居、以及分子间相互作用最重要的手段之一。近一个世纪以来,随着激光技术和分子光谱探测技术的发展,光频梳的发明等,使得分子光谱在高精密测量方面具有越来越多的应用:包括验证基本物理定律和对称性,以及测量精密物理常数,比如精细结构常数α、玻尔兹曼常数k_B等等。本论文的主要工作是通过自主发展并搭建的高精密光腔衰荡光谱(Cavity Ring-Down Spectroscopy)实验装置,利用频率锁定以及温度控制技术,示范进行高精密的分子光谱频率测量,并用于测定玻尔兹曼常数。本论文的主要内容包括以下几部分,第一章简要介绍了测量玻尔兹曼常数k_B的背景,以及目前国际上其他研究组主要采用的一些测量方法,比如声速法、介电常数发、热噪声法和多普勒展宽方法等,特别是本论文将采用的基于光腔衰荡光谱和多普勒展宽方法测定玻尔兹曼常数的原理。本章还介绍了光腔衰荡光谱方法的原理,以及对k_B测量有影响的各种加宽因素,包括碰撞加宽、渡越时间加宽、饱和加宽等等。第二章详细介绍了实验装置的设计与搭建,包括样品腔的机械设计与温度控制,激光频率的锁定与扫描等等。为了准确测定玻尔兹曼常数,我们不断改进实验方案,并且通过实际饱和吸收光谱的测量验证了实验方案的可行性。最终发展的实验方案不仅可以用于玻尔兹曼常数的测定,可能还可以用于其它高精密分子光谱测量。第三章介绍利用我们发展的三种实验设计方案所测量的结果与分析,对玻尔兹曼常数进行了初步测量结果与分析;同时发展了可用于分子兰姆凹陷测定的实验方法,并实现了精度达到亚kHz的CO分子饱和吸收光谱频率测定。最后,对于进一步的改进实验方法,实现高精密的k_B测定以及其它相关分子精密测量进行了讨论。
[Abstract]:Molecular spectrum is one of the most important means to study molecular structure, internal energy distribution and intermolecular interaction. In the last century, with the development of laser technology and molecular spectrum detection technology, the invention of optical frequency comb, etc. The molecular spectrum has more and more applications in high-precision measurement, including the verification of basic physical laws and symmetries, and the measurement of precise physical constants. For example, fine structure constant 伪, Boltzmann constant KB and so on. The main work of this thesis is to use frequency locking and temperature control technology through the self-developed and built high-precision optical cavity Ring-Down spectroscopy-based device. High precision molecular spectral frequency measurement is demonstrated and used to measure Boltzmann constant. The main contents of this paper include the following parts. The first chapter briefly introduces the background of the measurement of Boltzmann constant KSP B. And some of the main measurement methods used by other international research groups at present, such as sound velocity method, dielectric constant generation, thermal noise method and Doppler broadening method, etc. In particular, the principle of measurement of Boltzmann constant based on optical cavity ring-down spectrum and Doppler broadening method will be adopted in this paper. The principle of optical cavity ring-down spectrum method and various broadening factors affecting the measurement of KSP B are also introduced in this chapter. The second chapter introduces the design and construction of the experimental device in detail, including the mechanical design and temperature control of the sample cavity. Laser frequency locking, scanning and so on. In order to determine Boltzmann constant accurately, we constantly improve the experimental program. The feasibility of the experimental scheme is verified by the measurement of the actual saturated absorption spectrum. The developed experimental scheme can be used not only for the determination of Boltzmann constant, but also for the measurement of the Boltzmann constant. It may also be used for other high-precision molecular spectrometric measurements. In Chapter 3, the results and analysis of Boltzmann constant are presented and analyzed by using three experimental design schemes developed by us. At the same time, the experimental method which can be used for the determination of molecular Lamb sag is developed, and the saturated absorption spectrum frequency of CO with accuracy up to sub-#en0# is realized. Finally, for the further improvement of the experimental method, The realization of high precision Kappa B measurement and other related molecular precision measurements are discussed.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O657.3

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