Stimulated emission in the 16 μm range by rotational stimulated Raman scattering in parahydrogen

The development of an oscillator utilizing rotational stimulated Raman scattering of CO₂ laser radiation in parahydrogen tunable between 13 and 18 μm is reported. The process was achieved in a multipass optical cell at T = 77 K and a parahydrogen pressure p = 0.6 atm. Measurements were made of the energy of the Stokes radiation and the pump radiation transmitted by the cell as a function of the pump radiation energy. The maximal energy of the λ_s = 16 μm Stokes radiation was 0.63 J at a pump energy of 3.3 J. Appreciable losses of the radiation energy were observed in the cell.