Part-per-million gas detection from long-baseline THz spectroscopy

摘要

We report a long-baseline THz time domain spectrometer based on a White cell design capable of detecting gas species in the low part-per-million range in near real time. Coherent transients from methyl chloride vapor are observed directly in the time domain using a 5.0 m path length at pressures down to 1 Pa. Both phase sensitive (lock-in) detection and direct signal averaging using a rapid-scanning delay line are used for data acquisition. (C) 2004 American Institute of Physics.