Efficient high-power diffraction-limited fiber laser with a record low quantum defect of 1.7%

In this work, we demonstrate an approach to potentially lower the quantum defect to similar to 1% without significant compromise of efficiency. In a first demonstration, a diffraction-limited similar to 154 W laser emitting at similar to 993 nm with negligible amplified spontaneous emission, pumped at similar to 976 nm, was achieved with a slope efficiency of similar to 75% vs the launched pump power. The laser quantum defect is a record low of 1.7% for high-power (>100 W) solid-state lasers to the best of our knowledge. The output is only limited by the available pump power. (c) 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(https://creativecommons.org/licenses/by/4.0/).