Transient absorption and laser gain in e-beam-excited Ar/Kr/NF₃(F₂ + N₂) gas mixtures

Abstract

Newly developed erosion-plasma-source probe technique has been applied for virtually single shot recording of absorption/fluorescence spectra in the 190-510 nm spectral range of e-beam-excited Ar/Kr/NF 3 (F 2 + N 2 ) mixtures. The e-beam excitation rate of about 1 MW/cm 3 is typical of large-volume rare-gas halide lasers. It is experimentally observed that, in Kr/F 2 and Ar/F 2 mixtures, fluorescence and absorption spectra of Rg 2 F species are shifted with respect to each other in the opposite direction. Continuous absorption spectrum of Ar 2 F excimer is reported, as far as we know, for the first time in the refereed literature. Strong overlapping between the fluorescence and absorption spectra of Ar 2 F is responsible for absence of lasing on Ar 2 F molecule. Absorption spectrum of Kr 2 F excimer is recorded in pure form using the mixture (Ne/Kr/F 2 ) with no alternative broadband absorber. Minor additive of nitrogen to Ar/Kr/F 2 mixture or use of NF 3 instead of F 2 has been found to result in broadband optical amplification centered at λ ∼ 460 nm. The maximum optical gain is estimated as about 0.1 ± 0.05 m −1 .