Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

A quantitative study of the practical sensitivity limit of a terahertz absorption spectrometer.

Published

Author(s)

Jon E. Bjarnason, Charles Dietlein, Erich N. Grossman

Abstract

In gas spectroscopy, chemicals can be identified by the set of frequencies at which their absorption lines occur. The concentration can be quantitatively estimated from the intensity of any of the absorption lines. The sensitivity of the spectrometer, i.e., the minimum detectable concentration, is ideally limited by the ratio of the source power to detector noise-equivalent power. In practice, the sensitivity is usually orders of magnitude worse due to systematic effects. In this work we built a simple gas terahertz transmission spectrometer to analyze how the source output power stability, the detector sensitivity, and atmospheric pressure affect its sensitivity. As a test gas we used methyl chloride in a mixture with air and modifid the widths of the absorption lines by changing partial pressure of air. This demonstration of a simple absorption spectrometer gives us insight into the approach to making a highly sensitive terahertz spectrometer.
Proceedings Title
Proc. of SPIE
Volume
Vol. 6949
Conference Dates
March 18-21, 2008
Conference Location
Orlando, FL
Conference Title
SPIE - The International Society for Optical Engineering, Defense & Security Symposium

Keywords

Spectroscopy, methyl chlorde, linewidth, pressure broadening.

Citation

Bjarnason, J. , Dietlein, C. and Grossman, E. (2008), A quantitative study of the practical sensitivity limit of a terahertz absorption spectrometer., Proc. of SPIE, Orlando, FL, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=32980 (Accessed July 24, 2024)

Issues

If you have any questions about this publication or are having problems accessing it, please contact reflib@nist.gov.

Created March 18, 2008, Updated February 19, 2017