Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Frontiers in Optics

Laser cooling in rare earth doped BaY2F8 crystals

Wendy M. Patterson, Anca Mocofanescu, M. Sheik-Bahae, Richard I. Epstein, J. Thiede, Stefano Bigotta, Daniela Parisi, A. Toncelli, M. Tonelli

Published Jan 1, 2005• 2 citations
Publisher

Abstract

Laser cooling in thulium- and ytterbium-doped BaY2F8 crystals is observed. We investigate the potential of this crystalline host for all-solid-state cryocooler applications as compared to those based on rare-earth doped ZBLANP systems.
DOI
10.1364/fio.2005.jwa78

Related papers

Recent advances in laser cooling of solids

Galina A. Nemova, Raman Kashyap

The recent achievements devoted to cooling of solids with a laser are presented in this paper. We discuss the latest results of traditional laser cooling of solids based on rare earth ions and new techniques based on colloidal lead-salt quantum dots doped in a glass host, laser cooling in Tm3+-doped oxy-fluoride glass ceramic. Relatively short (microsecond) lifetime of the excited level of the PbSe QDs compared to the millisecond lifetime of the excited level of RE ions allows an acceleration of the cooling process and provides an opportunity to use new materials with higher phonon energy as hosts, which are normally considered unsuitable for cooling with RE ions. Another new approach to the laser cooling problem based on super-radiance has been considered in this paper. The advantages of optical refrigeration with rare earth doped semiconductors, in which not only optically active electrons of the 4f shell but the valence and conduction bands of the host material are involved in cooling cycle is discussed. It is shown that involving the valence and conduction bands of the host in the cooling cycle allows the pump wavelength to be shorter than mean fluorescence wavelength. Raman laser cooling of solids as well as observation of spontaneous Brillouin cooling have been presented.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Oct 11, 2013•3 citations

Laser cooling efficiency of Yb-doped yttrium aluminum oxide crystals

Takashi Kita, Yuta Nakayama

Cooling via efficient emission of anti-Stokes photoluminescence can be utilized to realize novel cooling devices. It has been shown that rare earth-doped materials are good candidates for solid-state laser cooling because of their narrow emission spectra and discrete energy levels. We systematically study laser cooling efficiency of rare earth-doped oxide crystals. The photoluminescence spectrum evidences that the phonon-assisted energy transfer from resonant states to inhomogeneously distributed energy states sensitively depends on temperature. We discuss detailed properties of the cooling efficiency of Yb-doped yttrium aluminum oxide crystals and, furthermore, touch emission properties of their crystal thin films.

Photonic Heat Engines: Science and Applications•Mar 4, 2021•0 citations

Spectroscopic and laser cooling results on Yb3+-doped BaY2F8 single crystal

Stefano Bigotta, Daniela Parisi, Lucia Bonelli +3 more

Anti-Stokes cooling has been observed in an Yb3+-doped BaY2F8 single crystal. Single crystals have been grown by the Czochralski technique. The absorption spectra and the emission properties have been measured at room temperature and at 10K. The energy positions of the Stark sublevels of the ground and the excited state manifolds have been determined and separated from the vibronic substructure. The intrinsic decay time of the F5∕22 level has been measured taking care of avoiding the effect of multiple reabsorption processes. The theoretical and experimental cooling efficiencies of Yb:BaY2F8 are evaluated and compared with respect to those of the most frequently investigated materials for laser cooling. A temperature drop of almost 4K was measured by pumping the crystal with 3W of laser radiation at ∼1025nm in single pass configuration with a cooling efficiency of ∼3%.

Journal of Applied Physics•Jul 1, 2006•46 citations

Alternative technique for laser cooling with superradiance

Galina A. Nemova, Raman Kashyap

We present a theoretical scheme for laser cooling of rare-earth-doped solids with optical superradiance (SR), which is the coherent, sharply directed spontaneous emission of photons by a system of laser-excited rare-earth ions in the solid-state host (glass or crystal). We consider an Yb${}^{+}$-doped ZnF${}_{4}$-BaF${}_{2}$-LaF${}_{3}$-AlF${}_{3}$-NaF (ZBLAN) sample pumped at a wavelength 1015 nm, with a rectangular pulsed source with a power of \ensuremath{\sim}433 W and a duration of 10 ns. The intensity of the SR is proportional to the square of the number of excited ions. This unique feature of SR permits an increase in the rate of the cooling process in comparison with the traditional laser cooling of the rare-earth-doped solids with anti-Stokes spontaneous incoherent radiation (fluorescence). This scheme overcomes the limitation of using only low phonon energy glasses for laser cooling.

arXiv:1007.3277•Physical Review A•Jan 19, 2011•16 citations

Laser cooling with nanoparticles

Galina A. Nemova, Elton Soares de Lima Filho, Sébastien Loranger +1 more

Theoretical schemes for laser cooling with nanoparticles have been presented and comprehensively investigated. It is shown that specially designed samples based on nanoparticles can be used to improve the process of laser cooling of solids. One of the proposed schemes is based on lead salt colloidal quantum dots (QDs) doped in a glass host. The second one is based on Tm3+ doped oxy fluoride glass ceramic. It has been shown that lead salt colloidal QDs doped in a glass host can operate as artificial atoms. Very short (microsecond range) radiative lifetimes of the excited 1Sh level of PbSe QDs in comparison with the relatively long (millisecond) radiative lifetime of rare-earth (RE) ions allows the cooling process to be accelerated and to use new hosts with relatively high maximum phonon energy, which have so far been considered not suitable for cooling with RE ions. It has been shown that the second sample, which is based on Tm3+ doped oxy fluoride glass ceramic provides the unique combination of high chemical and mechanical stability of the oxide glass, which is important for a number of applications, and the low phonon energy of the fluoride nano-crystals, which trap a majority of Tm3+ ions participating in the cooling process. This is highly beneficial for laser cooling of solids, since the effective embedding of rare-earth ions in the crystalline phase with low phonon energy provides a high quantum efficiency for the 3F4 → 3H6 transition involved in the cooling cycle in the Tm3+ ions, which is a key parameter for laser cooling of solids.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Oct 23, 2012•4 citations

Temperature distribution in laser-cooled rare-earth doped solid-state samples

Galina A. Nemova, Raman Kashyap

We present a comprehensive investigation of the temperature distribution in laser-cooled cylindrical solid-state samples doped with rare-earth ions. We consider Yb3+-doped fluorozirconate samples pumped at a wavelength of 1015 nm with Gaussian and “Top-Hat” pump beams. The influence of the parameters of a beam on the temperature distribution is investigated in detail for optimizing the sample design for the all-optical cryocooler.

Journal of the Optical Society of America B•Nov 1, 2010•3 citations
The recent achievements devoted to cooling of solids with a laser are presented in this paper. We discuss the latest results of traditional laser cooling of solids based on rare earth ions and new techniques based on colloidal lead-salt quantum dots doped in a glass host, laser cooling in Tm3+-doped oxy-fluoride glass ceramic. Relatively short (microsecond) lifetime of the excited level of the PbSe QDs compared to the millisecond lifetime of the excited level of RE ions allows an acceleration of the cooling process and provides an opportunity to use new materials with higher phonon energy as hosts, which are normally considered unsuitable for cooling with RE ions. Another new approach to the laser cooling problem based on super-radiance has been considered in this paper. The advantages of optical refrigeration with rare earth doped semiconductors, in which not only optically active electrons of the 4f shell but the valence and conduction bands of the host material are involved in cooling cycle is discussed. It is shown that involving the valence and conduction bands of the host in the cooling cycle allows the pump wavelength to be shorter than mean fluorescence wavelength. Raman laser cooling of solids as well as observation of spontaneous Brillouin cooling have been presented.
Cooling via efficient emission of anti-Stokes photoluminescence can be utilized to realize novel cooling devices. It has been shown that rare earth-doped materials are good candidates for solid-state laser cooling because of their narrow emission spectra and discrete energy levels. We systematically study laser cooling efficiency of rare earth-doped oxide crystals. The photoluminescence spectrum evidences that the phonon-assisted energy transfer from resonant states to inhomogeneously distributed energy states sensitively depends on temperature. We discuss detailed properties of the cooling efficiency of Yb-doped yttrium aluminum oxide crystals and, furthermore, touch emission properties of their crystal thin films.
Anti-Stokes cooling has been observed in an Yb3+-doped BaY2F8 single crystal. Single crystals have been grown by the Czochralski technique. The absorption spectra and the emission properties have been measured at room temperature and at 10K. The energy positions of the Stark sublevels of the ground and the excited state manifolds have been determined and separated from the vibronic substructure. The intrinsic decay time of the F5∕22 level has been measured taking care of avoiding the effect of multiple reabsorption processes. The theoretical and experimental cooling efficiencies of Yb:BaY2F8 are evaluated and compared with respect to those of the most frequently investigated materials for laser cooling. A temperature drop of almost 4K was measured by pumping the crystal with 3W of laser radiation at ∼1025nm in single pass configuration with a cooling efficiency of ∼3%.
We present a theoretical scheme for laser cooling of rare-earth-doped solids with optical superradiance (SR), which is the coherent, sharply directed spontaneous emission of photons by a system of laser-excited rare-earth ions in the solid-state host (glass or crystal). We consider an Yb+{}^{+}+-doped ZnF4{}_{4}4​-BaF2{}_{2}2​-LaF3{}_{3}3​-AlF3{}_{3}3​-NaF (ZBLAN) sample pumped at a wavelength 1015 nm, with a rectangular pulsed source with a power of \ensuremath{\sim}433 W and a duration of 10 ns. The intensity of the SR is proportional to the square of the number of excited ions. This unique feature of SR permits an increase in the rate of the cooling process in comparison with the traditional laser cooling of the rare-earth-doped solids with anti-Stokes spontaneous incoherent radiation (fluorescence). This scheme overcomes the limitation of using only low phonon energy glasses for laser cooling.
Theoretical schemes for laser cooling with nanoparticles have been presented and comprehensively investigated. It is shown that specially designed samples based on nanoparticles can be used to improve the process of laser cooling of solids. One of the proposed schemes is based on lead salt colloidal quantum dots (QDs) doped in a glass host. The second one is based on Tm3+ doped oxy fluoride glass ceramic. It has been shown that lead salt colloidal QDs doped in a glass host can operate as artificial atoms. Very short (microsecond range) radiative lifetimes of the excited 1Sh level of PbSe QDs in comparison with the relatively long (millisecond) radiative lifetime of rare-earth (RE) ions allows the cooling process to be accelerated and to use new hosts with relatively high maximum phonon energy, which have so far been considered not suitable for cooling with RE ions. It has been shown that the second sample, which is based on Tm3+ doped oxy fluoride glass ceramic provides the unique combination of high chemical and mechanical stability of the oxide glass, which is important for a number of applications, and the low phonon energy of the fluoride nano-crystals, which trap a majority of Tm3+ ions participating in the cooling process. This is highly beneficial for laser cooling of solids, since the effective embedding of rare-earth ions in the crystalline phase with low phonon energy provides a high quantum efficiency for the 3F4 → 3H6 transition involved in the cooling cycle in the Tm3+ ions, which is a key parameter for laser cooling of solids.