A continuous-wave mid-IR diode-laser-based, dual-cavity difference-frequency spectrometer employing silver thiogallate (AgGaS 2) as the down-conversion material, and producing only 30 nW of usable mid-IR output, is used to record Doppler spectra of NH3 and SF6 around 10.2 μm and 10.5 μm over the 90-GHz range. The tuning procedure of the spectrometer as well as a baseline noise cancellation technique based on analogue signal ratioing are described. The device can potentially be used for ultra-high-resolution saturation spectroscopy, pending an improvement of the down-conversion efficiency to l-μW power.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)
- Physics and Astronomy(all)