Laser Cooling of a Solid by 16 K Starting from Room Temperature

摘要: An Yb{sup 3+}-doped optical fiber is laser cooled {ital in vacuo}from 298 to 282K. Cooling results from anti-Stokes fluorescence of the ytterbium ions after pumping at a wavelength 1015nm. The sample temperature deduced emission spectrum, which sensitive populations excited-state multiplet ions. change limited by coupling between and ambient blackbody radiation, as confirmed when samples suddenly exposed pump are found exponentially relax towards thermal steady state with expected time constants. {copyright} 1997} American Physical Society}