Deuterium fluoride chemical laser with diffraction-limited beam divergence

An investigation was made into the possibility of achieving the diffraction-limited beam divergence from a pulsed flashlamp-pumped DF chemical laser on replacing its plane resonator with an unstable resonator of the telescopic type. Under the optimal operating conditions of the laser with the unstable resonator, a beam divergence of θ_(1/2)E = 70 μ rad was obtained (practically equal to the diffraction limit) with quite a high energy efficiency (~60%) relative to that of a similar laser having a plane resonator. It was found experimentally that by appropriately "detuning" the unstable resonator one could make measurements of the radiation energy distribution in the far-field zone without employing additional focusing elements.