Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1493214 | Optical Materials | 2016 | 4 Pages |
Abstract
The fluorescence of CaF2 single-crystals containing Eu2+ ions was studied under the excitation in the long-wavelength tail of the absorption spectrum which is due to electric dipole allowed transitions (“laser cooling regime”). Though no actual cooling was detected, spectra with a dominant anti-Stokes component were observed which demonstrate the possibility to employ electron-phonon bands of Eu2+ f-d transitions for optical refrigeration. The absence of observable optical refrigeration is ascribed to Eu2+ two-step photoionization processes that are responsible for the excited state absorption. The role of two-step excitation of impurity centers (excited state absorption) in laser cooling experiments is discussed.
Related Topics
Physical Sciences and Engineering
Materials Science
Ceramics and Composites
Authors
S.P. Feofilov, A.B. Kulinkin, V.A. Konyushkin, A.N. Nakladov,