Spectral kinetics and emission cross-sections of 3 <i>μ</i>m transitions in pulsed Er:YLF lasers at room and cryogenic temperatures

Abstract We thoroughly investigate the spectral kinetics of a diode-pumped, free-running, pulsed 3 μ m Er:YLF laser at cryogenic and room temperatures and show that spectroscopically-derived emission cross-sections of the 3 μ m laser transitions in Er 3+ do not allow correctly predicting the experimentally observed multiwavelength spectral kinetics of the laser output. ‘True’ emission cross-sections were determined through detailed modeling of the laser dynamics, anchored by experimentally derived thresholds for successively lasing inter-Stark transitions between the 4 I 11/2 and 4 I 13/2 manifolds. These revised cross-sections also finally eliminate the existing major discrepancies in the literature data on emission cross-sections in Er:YLF.