Trace gas detection of C2H4 by photoacoustic spectroscopy using a compact pulsed optical parametric oscillator

摘要

A compact pulsed optical parametric oscillator operated in an optical cavity with a grazing-incidence grating configuration was used to demonstrate sensitive photoacoustic detection of trace quantities of ethylene (C2H4). An IR wavelength within the absorption band of ethylene that produces minimal signal interference by background gases was identified. Using this IR wavelength, a concentration sensitivity of 10 parts in 10(9) by volume of C2H4 in nitrogen was measured with 60 mW of IR power in a single-pass configuration. The method of measuring the signal by fixing the IR wavelength at the absorption peak was compared with that of scanning the IR wavelength across the absorption maximum.