Cross-relaxation and temporal dynamics of lasing at 2 μm in thulium-doped ceramic material

Year: 2025

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

Autors Affiliation: Ist Nazl Ott CNR INO, Consiglio Nazl Ric, Intense Laser Irradiat Lab ILIL, Pisa, Italy; Ist Nazl Ott CNR INO, Consiglio Nazl Ric, Sesto Fiorentino, Italy.

Abstract: We report the characterization of the pump absorption and emission dynamic properties of a $mathrm{Tm}:{mathrm{Lu}}_2{mathrm{O}}_3$ ceramic lasing medium using a three-mirror folded laser cavity. We measured a slope efficiency of 73%, which allowed us to retrieve the cross-relaxation coefficient. The behavior of our system was modeled via a set of macroscopic rate equations 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.

Journal/Review: HIGH POWER LASER SCIENCE AND ENGINEERING

Volume: 13      Pages from: e51-1  to: e51-8

More Information: The authors acknowledge the following funding: EU Horizon 2020 Research and Innovation Program EuPRAXIA Preparatory Phase, under Grant Agreement No. 101079773, EU Horizon IFAST, under Grant Agreement No. 101004730. This research has been co-funded by the European Union – NextGeneration EU ’Integrated infrastructure initiative in Photonic and Quantum Sciences’ – I-PHOQS (IR0000016, ID D2B8D520, CUP B53C22001750006) and ’EuPRAXIA Advanced Photon Sources’ – EuAPS (IR0000030, CUP I93C21000160006). We also acknowledge the contribution to the strategic view of this research by the Project ’Tuscany Health Ecosystem – THE’ ’Spoke 1 – Advanced Radiotherapies and Diagnostics in Oncology’ funded by the NextGenerationEU (PNRR), Codice progetto ECS00000017, D.D. MUR No. 1055 23 May 2022.
KeyWords: high average power laser; ceramic laser materials; diode pumping; multipulse extraction; cross relaxation process
DOI: 10.1017/hpl.2025.37