Purcell-enhanced optical refrigeration

Authors:
Open Access
Publisher website
Google Scholar
Abstract
Optical refrigeration of solids with anti-Stokes fluorescence has been widely explored as a vibration-free cryogenic cooling technology. A minimum temperature of 87 K has been demonstrated with rare-earth-ion-doped crystals using optical refrigeration. However, the depletion of the upper-lying energy levels in the ground-state manifold hinders further cooling to below the liquid nitrogen ( LN 2 ) temperatures, restricting its applications. In this work, we introduce a Purcell-enhanced optical refrigeration method to circumvent this limitation. This approach enhances the emission of high-energy photons by coupling the emitters to an optical cavity, blueshifting the mean emission wavelength. Such Purcell-enhanced emission facilitates cooling starting from a lower-energy level in the ground-state manifold, which exhibits a higher occupation below the LN 2 temperatures. Using experimentally measured optical coefficients, our theoretical analysis predicts a minimum achievable internal temperature of about 38 K for a Yb 3 + : YLiF 4 nanocrystal near a cavity under realistic conditions. The proposed method is applicable to other rare-earth-ion-doped materials and semiconductors and will have applications in creating superconducting and other quantum devices through solid-state cooling.
Funding Information
  • National Science Foundation (PHY-2409607)
  • National Science Foundation (EEC-2224960)
  • Office of Naval Research (N00014-18-1-2371)

This publication has 49 references indexed in Scilit: