Semiconductor-laser heterodyne frequency measurements on 152-μm molecular transitions

Abstract
A near-infrared semiconductor-laser spectrometer has been heterodyned with a Lamb-dip-stabilized 1.52-μm 3He–20Ne laser for frequency calibration of molecular spectra. Absolute frequencies of 30 vibration–rotation transitions of acetylene (12C2H2, 12C13CH2, 13C2H2), hydrogen cyanide, ammonia (14NH3, 15NH3), and deuterated water (D2O, HDO) molecules have been measured within 20 GHz of the 3He–20Ne-laser frequency.