Mie Resonance Enhancement of Laser Cooling in Rare-Earth Doped Materials

TL;DR

This paper demonstrates that using Mie resonances in rare-earth doped nanoparticles significantly enhances laser cooling efficiency, enabling substantial temperature reductions and broadening potential applications.

Contribution

It introduces a novel approach of leveraging Mie resonances to boost anti-Stokes fluorescence laser cooling in RE-doped nanoparticles, showing notable temperature decrease.

Findings

Mie resonances can enhance cooling power density.

Temperature of nanoparticles can be reduced by approximately 63%.

The method is adaptable to various nanoparticle shapes and materials.

Abstract

Laser cooling of solids keeps attracting attention owing to abroad range of its applications that extends from cm-sized all-optical cryocoolers for airborne and space-based applications to cooling on nanoparticles for biological and mesoscopic physics. Laser cooling of nanoparticles is a challenging task. We propose to use Mie resonances to enhance anti-Stokes fluorescence laser cooling in rare-earth (RE) doped nanoparticles made of low-phonon glasses or crystals. As an example, we consider an Yb3+:YAG nanosphere pumped at the long wavelength tail of the Yb3+ absorption spectrum at 1030 nm. We show that if the radius of the nanosphere is adjusted to the pump wavelength in such a manner that the pump excites some of its Mie resonant modes, the cooling power density generated in the sample is considerably enhanced and the temperature of the sample is consequently considerably (~ 63%) decreased. This concept can be extended to nanoparticles of different shapes and made from different low-phonon RE doped materials suitable for laser cooling by anti-Stokes fluorescence.