Work

Observation of Laser Cooling on an Electric‐Dipole‐Allowed Transition in Cr 3+ :LiSAF Crystal

Year: 2025

Type: article

Abstract: In this work, an electric dipole allowed transition in two Cr 3+ :LiSAF samples is investigated for the purpose of optical refrigeration. A cooling efficiency approaching 10% is experimentally determined using a mode‐mismatched dual‐beam thermal lens method with excitation wavelength, , of 1 µm in an unoriented 1% Cr 3+ :LiSAF, which has an average emission wavelength, , of 850 nm. In an oriented 4% Cr 3+ :LiSAF sample, the efficiency reached (but does not exceed) the threshold for cooling when excited with π‐polarized light. These results suggest that Cr 3+ :LiSAF can approach an ideal cooling efficiency ∼ with excitation ≈1µm. Additionally, this analysis indicates that parasitic background absorption rather than upconversion or excited state absorption limits the cooling at higher Cr 3+ concentrations.

Source: Advanced Optical Materials

DOI: 10.1002/adom.202403222

Authors: Junior Reis Silva, Luis Humberto da Cunha Andrade, Sandro Marcio Lima, Antônio Carlos Bento, Tomaz Catunda, Stephen Colby Rand