Tunable Raman laser based on the third Stokes component of liquid nitrogen

Stimulated emission was obtained at a wavelength of 4 μ (with continuous tuning within 0.15 μ) as a result of conversion of neodymium laser radiation into the third Stokes component in a liquid nitrogen Raman laser. The output radiation of the Raman laser was used to determine the isotopic structure and spectroscopic characteristics of the P(4) line of the principal vibrational band of the HBr molecule. The measured isotopic shift was 0.29±0.05 cm^–1.