A gas laser which makes use of electronic, vibrational or rotational energy levels in molecules. The molecules can be excited by an electric discharge, as in the case of the
N2 or
CO2 laser, by chemical reactions, as in the
HF or
DF lasers, or by another laser, as in the
CH3F far IR laser.
Source:
PAC, 1995, 67, 1913. 'Nomenclature, symbols, units, and their usage in spectrochemical analysis-XV. Laser-based molecular spectroscopy for chemical analysis - laser fundamentals (IUPAC Recommendations 1995)' on page 1920 (https://doi.org/10.1351/pac199567111913)