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Segmented chirped-pulse Fourier transform submillimeter spectroscopy for broadband gas analysis

Published

Author(s)

Justin L. Neill, Brent J. Harris, Amanda L. Steber, Kevin O. Douglass, David F. Plusquellic, Brooks H. Pate

Abstract

Chirped-pulse Fourier transform spectroscopy has recently been extended to millimeter wave spectroscopy as a technique for the characterization of room-temperature gas samples. Here we present a variation of this technique that significantly reduces the technical requirements on high-speed digital electronics and the data throughput, with no reduction in the broadband spectral coverage and no increase in the time required to reach a given sensitivity level. This method takes advantage of the frequency agility of arbitrary waveform generators by utilizing a series of low-bandwidth chirped excitation pulses paired in time with a series of offset single frequency local oscillators, which are used to detect the molecular free induction decay signals in a heterodyne receiver. A demonstration of this technique is presented in which a 67 GHz bandwidth spectrum of methanol (spanning from 792 to 859 GHz) is acquired in 58 υs.
Citation
Optics Express
Volume
21
Issue
17

Keywords

emission, far infrared or terahertz, heterodyne, solid-state detectors, spectrometers and spectroscopic instrumentation, spectroscopy
Created August 15, 2013, Updated November 10, 2018