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Inert shell coating for enhanced laser refrigeration of nanoparticles: application in levitated optomechanics

Optics 2026-04-30 v2 Mesoscale and Nanoscale Physics Quantum Physics

Abstract

We report on a study exploring the design of nanoparticles that can enhance their laser refrigeration efficiency for applications in levitated optomechanics. In particular, we developed lanthanide-doped nanocrystals with an inert shell coating and compared their performance with bare nanocrystals. While optically levitated, we studied the refrigeration of both types of nanoparticles while varying the pressure. We found that the core-shell design shows an improvement in the minimum final temperature: a fourth of the core-shell nanoparticles showed a significant cooling compared to almost none of the bare nanoparticles. Furthermore, we measured a core-shell nanoparticle cooling down to a temperature of 147 K at 26 mbar in the underdamped regime. Our study is a first step towards engineering nanoparticles that are suitable for achieving absolute (centre-of-mass and internal temperature) cooling in levitation, opening new avenues for force sensing and the realization of macroscopic quantum superpositions.

Keywords

Cite

@article{arxiv.2307.02240,
  title  = {Inert shell coating for enhanced laser refrigeration of nanoparticles: application in levitated optomechanics},
  author = {Cyril Laplane and Peng Ren and Reece P. Roberts and Yiqing Lu and Thomas Volz},
  journal= {arXiv preprint arXiv:2307.02240},
  year   = {2026}
}

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