An ultra-high-resolution offset-locked carbon dioxide laser spectrometer

Abstract
An ultra-high-resolution frequency-offset-locked carbon dioxide waveguide laser spectrometer has been constructed. Three different sample cell configurations have been evaluated, namely: plane-plane etalon, mirror-based two-pass cell and a retro-reflector-based two-pass cell. In the last case peak-to-peak linewidths of 12 kHz have been obtained for the first derivative signal in sulphur hexafluoride at 10.6 mu m.