Raman laser utilizing rotational levels of hydrogen with a ring resonator

An investigation was made of a ring-resonator Raman laser utilizing rotational levels in the ortho-hydrogen molecule. It was found that stimulated Raman scattering due to vibrational levels of the molecule and the higher-order Stokes components of rotational stimulated Raman scattering can be efficiently suppressed in a ring resonator with polarization selection. A power conversion efficiency of 53% was achieved for unidirectional lasing.