Application of unstable telescopic resonators in generation of low-divergence radiation in a pulsed chemical SF6–H2 laser with electron-beam initiation

A study was made of the divergence of the radiation generated using unstable telescopic resonators in a pulsed chemical SF₆–H₂ laser initiated by a transverse electron beam. The duration of laser radiation pulses was ~ 100 ns. Initiation of the active medium resulted in a strong transverse inhomogeneity. It was possible to use telescopic resonators to ensure that the divergence of the output radiation was reduced to ~ 0.15 mrad, which was close to the diffraction limit (~ 0.05 mrad). The laser radiation energy in the far-field zone was then ~ 0.2 J. The energy efficiency in the formation of the radiation was ~ 20%. Comparison with the same laser, but with a plane–plane resonator showed that the axial density was two orders of magnitude higher and the angular divergence was two orders of magnitude lower.