Amplification of laser radiation at the edge of the KrF (B–X) spectral line

Abstract

We report the results of experimental and numerical studies of the KrF electric discharge amplifier operating on a mixture of He – Kr – F2 gases. The possibility of expanding the short-wavelength spectral region of the induced radiation tuning at the B – X transition of the KrF molecule by removing the inverse population from the upper vibrational states of the electronic B level is shown. It is demonstrated that at the boundary of the active medium gain contour, the measured gain at a wavelength of 246.8 nm is 0.053 cm−1. Using the developed 1D model of the KrF electric discharge amplifier, it is shown that when the active medium is excited by a pump pulse with a specific peak power of ∼10 MW cm−3, the gain in this spectral region is due to a longer relaxation time of the population of excimer molecules from the upper vibrational levels compared with the characteristic time of their production.