Optical refrigeration: the role of parasitic absorption at cryogenic temperatures

Cryogenic optical refrigeration

We review the field of laser cooling of solids, focusing our attention on the recent advances in cryogenic cooling of an ytterbium-doped fluoride crystal (Yb:YLiF4). Recently, bulk cooling in this material to 155 K has been observed upon excitation near the lowest-energy (E4–E5) crystal-field resonance of Yb3+. Furthermore, local cooling in the same material to a minimum achievable temperature ...

Refractive Index of ZnSe at Cryogenic Temperatures†

This report describes an extensive data set on the refractive index of ZnSe that provides full high resolution coverage of the CRIRES operating range in both wavelength and temperature. By combining our prototype instrument model of CRIRES with these data our project to provide wavelength calibration for IR Echelle spectrographs (WIRE) has reached an important milestone and is ready to support ...

the role of application of dynamic assessment approach in improvement of iranian efl writing performance at different language proficiency levels

the present study sought to investigate the role of dynamic assessment (da) in improvement of iranian efl writing performance at different language proficiency levels. to this end, after conducting the quick placement test, 60 iranian efl learners were assigned to two groups with different language proficiency levels. in both groups each participant wrote two compositions, one before and one af...

Characterization of the Opa350 Operational Amplifier at Cryogenic Temperatures

As part of the development of EMIR, an infrared multiobject spectrograph for the Gran Telescopio de Canarias (GTC), the OPA350 operational amplifier is being successfully used at cryogenic temperatures (77K). The use of off-theshelf electronics (not specifically designed for cryogenics) is advantageous since it allows us to get signal amplification very close to the detector without the need of...

Investigation of the Tribological Behavior of Polytetrafluoroethylene at Cryogenic Temperatures