Anti-Stokes Cooling of Nanoparticle-Doped Silica Fibers

Pierre Baptiste Vigneron, Bailey Meehan, Mary Ann Cahoon, Thomas W. Hawkins, John Ballato, Peter D. Dragic, Magnus Engholm, Tommy Boilard, Martin Bernier, Michel J.F. Digonnet

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The recent reports of laser cooling in Yb-doped aluminosilicate fibers and silica preforms have opened up the field of optical refrigeration and radiation-balanced lasers to the enormous realm of silica fiber lasers and amplifiers. To increase the cooling efficiency achieved in these materials, it is critical to identify host compositions that improve the Yb3+-ion properties in the directions of low concentration quenching, short radiative lifetime, and a long-wavelength absorption tail that extends as far as possible above the zero-phonon line. In this on-going quest, nanoparticle-doped fibers offer a promising technique to modify the chemical environment of the Yb3+ ions and achieve some of these properties. In this work, three fibers in which the Yb3+ ions are initially encapsulated in CaF2, SrF2, or BaF2 nanoparticles were fabricated using a solution-doping technique, and their laser-cooling properties evaluated experimentally and analyzed. The CaF2 fiber and the SrF2 fiber were successfully cooled at atmospheric pressure when pumped with a continuous-wave laser at the near-optimum wavelength of 1040 nm. The measured maximum temperature change from room temperature was -26.2 mK for the CaF2 fiber at a pump power absorption level of 90 mW/m, and -16.7 mK at 66 mW/m for the SrF2 fiber. The BaF2 fiber did not cool, but it warmed only slightly, indicating that it was not far from cooling. Analysis of the measured dependence of the fiber temperature change on pump power with a model enabled extraction of the fiber’s critical quenching concentration and residual absorptive loss due to impurities. Comparison of these values to the values reported for an aluminosilicate fiber and fiber preforms that cooled shows that the CaF2 and SrF2 fibers faired as well as the fiber, and better than the preforms, in terms of quenching, but that they had a higher absorptive loss. This study establishes the significant research potential of nanoparticle-doped fibers in the search for efficient laser-cooling silica hosts.

Original languageEnglish (US)
Title of host publicationPhotonic Heat Engines
Subtitle of host publicationScience and Applications IV
EditorsDenis V. Seletskiy, Masaru K. Kuno
ISBN (Electronic)9781510649071
StatePublished - 2022
EventPhotonic Heat Engines: Science and Applications IV 2022 - Virtual, Online
Duration: Feb 20 2022Feb 24 2022

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferencePhotonic Heat Engines: Science and Applications IV 2022
CityVirtual, Online


  • Yb-doped fiber
  • anti-Stokes fluorescence
  • anti-Stokes pumping
  • concentration quenching
  • laser cooling
  • nanoparticle fibers

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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