Experimental comparison of silica fibers for laser cooling

Jennifer Knall, Magnus Engholm, John Ballato, Peter D. Dragic, Nanjie Yu, Michel J.F. Digonnet

Research output: Contribution to journalArticlepeer-review


Laser cooling in silica has recently been demonstrated, but there is still a lack of understanding on how fiber composition, core size, and OH- contamination influence cooling performance. In this work, six Yb-doped silica fibers were studied to illuminate the influence of these parameters. The best fiber cooled by -70 mK with only 170 mW/m of absorbed pump power at 1040 nm, which corresponds to twice as much heat extracted per unit length compared to the first reported laser cooling in silica. This new fiber has an extremely low OH- loss and a higher Al concentration (2.0 wt.% Al), permitting a high Yb concentration (2.52 wt.% Yb) without incurring significant quenching. Strong correlations were found between the absorptive loss responsible for heating and the loss measured at 1380 nm due to absorption byOH-.

Original languageEnglish (US)
Pages (from-to)4020-4023
Number of pages4
JournalOptics Letters
Issue number14
StatePublished - Jul 15 2020
Externally publishedYes

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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