Intra-cavity cryogenic optical refrigeration using high power vertical external-cavity surface-emitting lasers (VECSELs).

A 7% Yb:YLF crystal is laser cooled to 131 ± 1 K from room temperature by placing it inside the external cavity of a high power InGaAs/GaAs VECSEL operating at 1020 nm with 0.15 nm linewidth. This is the lowest temperature achieved in the intracavity geometry to date and presents major progress towards realizing an all-solid-state compact optical cryocooler.