Transverse modulational instabilities in the presence of stimulated rotational Raman scattering with a high-energy laser.
Transverse modulational instabilities have been observed in two high-energy laser experiments. In one experiment a collimated laser beam with a 351-nm wavelength propagated through air and generated stimulated rotational Raman scattering. In the second experiment a 1-kJ laser pulse with a 1054-nm wavelength was focused into a spatial filter having a 50-microm residual pressure. In both experiments the transverse modulational instability took the form of a hexagonal emission pattern in the interaction region. The instability can be understood from an analysis in the plane-wave approximation.
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Skeldon