UV-pumped Tm:YLF lasers at 450 nm, 742 nm, and 1.9 µm
Year: 2026
Type: article
Abstract: We investigated the feasibility of blue laser operation around 450 nm in Tm:YLF on the 1 D 2 → 3 F 4 transition by detailed spectroscopic characterization and modeling. Absorption cross sections as well as temperature- and concentration-dependent fluorescence lifetimes of the relevant multiplets were measured, enabling the determination of the cross-relaxation macroparameters. From visible fluorescence and excited-state absorption, we derived emission and gain cross sections for the 1 D 2 → 3 F 4 transition near 450 nm, and used them as the input for a five-level rate-equation model, which predicts that room-temperature lasing at 450 nm requires induced depopulation of the long-lived 3 F 4 level, e.g., via cascade lasing. Experiments under 360-nm pumping enabled efficient 1.9-µm laser operation with 44% slope efficiency, indicating a three-for-one pumping mechanism enabled by cross-relaxation processes. Cascade lasing 1 D 2 → 3 F 4 → 3 H 6 was not achieved at room temperature due to insufficient pump power, but cryogenic cascade laser experiments at 85 K enabled 39 mW blue output at 450 nm with simultaneous 1879-nm lasing. Furthermore, we demonstrate laser operation at 742 nm for the first time at temperatures below 100 K. These results motivate exploration of alternative hosts and UV-diode pumping for compact blue Tm 3+ lasers.
Source: Optical Materials Express
DOI: 10.1364/ome.590031
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,843
OpenAlex ID: W7135195296