Cavity length matching and optical resonances in a Raman laser with the multimode pump source.

We report on the observation of local reduction in generation threshold and enhancement in the output energy of a nanosecond Raman laser when the round-trip time of its cavity is matched with that of a longitudinally multimode pump laser or related to the latter as a ratio of small integers. We refer both observations to the synchronous pump effect originating from the periodicity in the small-scale intensity structure of the pump pulse.

Bessel beam transformation by anisotropic crystals.

Transformation of Bessel beams by biaxial and uniaxial crystals is investigated experimentally and theoretically. Experimental observations show beam symmetry changing and formation of complex intensity patterns, depending on the orientation of the crystal. These patterns can appear as a regular system of peak intensities.