Open AccessFirst demonstration of optical refrigeration efficiency greater than 4% at room temperature
Author(s) -
Giovanni Cittadino,
Eugenio Damiano,
A. Di Lieto,
M. Tonelli
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.390283
Subject(s) - ytterbium , materials science , thulium , laser cooling , ion , refrigeration , optics , yttrium , lithium (medication) , doping , optoelectronics , laser , chemistry , thermodynamics , medicine , physics , organic chemistry , metallurgy , endocrinology , oxide
In this work, we present the cooling efficiency of a LiYF 4 (lithium yttrium fluoride,YLF) sample co-doped with 10at.% ytterbium (Yb 3+ ) and 0.0040at.% thulium (Tm 3+ ). For the first time at room temperature, the cooling efficiency of a sample overcomes the 4%-barrier, and it must be compared with the best values reported in literature, about 3%, obtained with a YLF:10at.%Yb sample. We also investigated the frequency behaviour of energy transfer mechanisms between Yb and Tm ions in order to have a better understanding of the contribution of phonons to the cooling cycle. These mechanisms can explain the cooling efficiency enhancement in the co-doped system.