Flashlamp-pumped liquid laser with a diffraction-limited beam divergence of 9 X 10 – 5 rad

An output beam having a divergence ψ_0.5^E = 9 X 10 ^– 5 rad at half-energy and a total beam energy of 0.7 J was obtained from a laser utilizing a solution of rhodamine 6G in ethanol excited by a flashlamp with a transverse discharge of 250-ns duration. An unstable telescopic resonator in the positive branch with a magnification of 3 was used to achieve this divergence, which corresponded to the diffraction limit at the laser exit aperture.