Investigation of kinetics of mid-infrared ASEs of Xe by two photon excitation

Abstract Optical pumped metastable rare gas lasers show great potential for high power operation. It is essential for understanding energy transfer processes between excited states of rare gas. In this work, two photon pumped laser induced amplified spontaneous emission (ASE) was used to study the kinetics of high lying state of Xe 6p'[1/2]0. Spectra and waveform of these ASEs were studied in the region of 1000–5000 nm when Xe was excited to the 6p'[1/2]0 state. Cascade transitions from the excited state were found to have two dominant channels which are 6p'[1/2]0 - 5d[1/2]1 - 6p[1/2]1 and 6p'[1/2]0–7s[3/2]1 - 6p(6p[5/2]2, 6p[3/2]1 and 6p[3/2]2). In addition, three delayed ASEs appeared when the Xe pressure is low. They are 3107 nm (5d[5/2]3 - 6p[3/2]2), 3368 nm (5d[5/2]2 - 6p[3/2]1) and 3508 nm (5d[7/2]3 - 6p[5/2]2). By the comparison of waveforms of cascade ASEs under different Xe pressures, prepared states by two photon excitation etc., it was found that 5d[5/2]3, 5d[5/2]2 and 5d[7/2]3 states of Xe were produced directly by collision relaxations and the corresponding relaxation rate constants were obtained by fitting the delay time of ASEs.