A study of cross-relaxation and temporal dynamics of lasing at 2 microns in Thulium doped ceramic

A. Fregosi, F. Brandi, L. Labate, F. Baffigi, G. Cellamare, M. Ezzat, D. Palla, G. Toci, A. Whitehead, L.A. Gizzi

High Power Laser Science and Engineering , Accepted manuscript , 1 - 9, 2025

Abstract

We report the characterization of the pump absorption and emission dynamic properties of a Tm: Lu2O3 ceramic lasing medium using a three mirrors folded laser cavity. We measured a slope efficiency of 73%, which allowed us to retrieve the cross-relaxation coefficient. Th e be havior of ou r sy stem wa s mo deled vi aa se t of ma croscopic ra te eq uations in both the quasi continuous wave and the pulsed pumping regime. Numerical solutions were obtained, showing a good agreement with the experimental findings. The numerical solution also yielded a cross-relaxation coefficient in very good agreement with the measured one, showing that the cross-relaxation phenomenon approaches the maximum theoretical efficiency.