Colour-centre laser observation of saturated absorption resonances at the R-branch lines of the ν3 band of the methane molecule

A tunable colour-centre laser was used in a study of Doppler-free saturated absorption resonances at the R lines of the V3 band of the methane molecule (A, = 3.2-3.3 um). The spectral resolution was 300 kHz for a configuration with an intracavity absorption cell. The laser is suitable for the investigation of any of the R and Q lines of the V3 methane band, and the long-wavelength limit of the tuning range reached the P(2) line.