Parametric Raman laser with a discrete output spectrum equal in width to the pump frequency

It has been shown analytically and numerically that the maximum width of the region occupied by the components of the stimulated Raman scattering with comparable intensities is equal to the pump frequency. Conditions for achieving this type of operation are formulated. During rotational stimulated Raman scattering of focused biharmonic radiation in hydrogen, eight anti-Stokes components and five Stokes components have been achieved, with relative intensities of 10^–3 and 10^–2, respectively. The divergence of these components was ~1.5–2.5 times the diffraction limit. The width of an individual line, δν, was no greater than 2 · 10^–2 cm^–1. The length of the Stokes components was much smaller than that of the anti-Stokes components. It is shown at a qualitative level that the reason for the significant discrepancy between the number of components predicted by the plane-wave theory and that found experimentally is a wave mismatch due to diffraction.