Dye laser with an output energy of 1 J, a beam divergence of 0.3 mrad, and flashlamp excitation

A study was made of the use of an unstable telescopic resonator in a laser utilizing an ethanol solution of rhodamine 6G excited by a coaxial transverse-discharge flashlamp. When the stored electrical energy was 300 J, the output energy of the laser was 1 J and the angle of divergence of the beam at half the maximum energy was 0.3 mrad. A mode structure of the radiation was observed within the limits of this angle and it was found that, in addition with the lowest symmetric modes, modes with a nonzero azimuthal index were generated. The kinetics of thermooptic distortions of the active medium was also investigated.