Researchers develop first self-cooling laser made with a silica fiber

Phys.org   March 17, 2021
An international team of researchers (USA – Stanford University, University of Illinois, Clemson University, Sweden, Canada) has achieved laser cooling in silica optical fiber with 21-µm diameter core doped with ytterbium and co-doped with aluminum oxide and fluoride ion to increase the critical quenching concentration by a factor of 16. Using a custom slow-light fiber Bragg grating sensor they measured temperature changes up to −50mK. The measured dependencies of the temperature change on the pump power and the pump wavelength were in excellent agreement with predictions from an existing model. To understand how fiber composition, core size, and contamination influence cooling performance they studied six Yb-doped silica fibers. The best fiber cooled by −70mK which corresponds to twice as much heat extracted per unit length compared to the first reported laser cooling in silica.  A self-cooling laser could be used to create advanced fiber amplifiers and low-power science applications aimed at gathering high-precision measurements of physical parameters such as acceleration, acoustic waves, or strain…read more. TECHNICAL ARTICLE  1  ,  2
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