Laser radiation has been used to cool matter ranging from dilute gases to micromechanical oscillators. In Doppler cooling of gases, the translational energy of atoms is lowered through interaction with a laser field(1,2). Recently, cooling of a high-density gas through collisional redistribution of radiation has been demonstrated(3). In laser cooling of solids, heat is removed through the annihilation of lattice vibrations in the process of anti-Stokes fluorescence(4-6). Since its initial observation in 1995, research(7-15) has led to achieving a temperature of 208 K in ytterbium-doped glass(16). In this Letter, we report laser cooling of ytterbium-doped LiYF(4) crystal to a temperature of similar to 155 K starting from ambient, with a cooling power of 90 mW. This is achieved by making use of the Stark manifold resonance in a crystalline host, and demonstrates the lowest temperature achieved to date without the use of cryogens or mechanical refrigeration. Optical refrigeration has entered the cryogenic regime, surpassing the performance of multi-stage Peltier coolers.
|Autori:||Seletskiy Denis V.; Melgaard Seth D.; Bigotta Stefano; Di Lieto Alberto; Tonelli M; Sheik-Bahae Mansoor|
|Titolo:||Laser cooling of solids to cryogenic temperatures|
|Anno del prodotto:||2010|
|Digital Object Identifier (DOI):||10.1038/NPHOTON.2009.269|
|Appare nelle tipologie:||1.1 Articolo in rivista|