scholarly journals Ideal Laser Cooling Efficiency Utilizing Anti-Stokes Luminescence in Yb-Doped Yttrium Aluminum Garnet Powder Crystals

2019 ◽  
Vol 68 (10) ◽  
pp. 762-766
Author(s):  
Yuta NAKAYAMA ◽  
Kota TERADA ◽  
Yukihiro HARADA ◽  
Takashi KITA
Keyword(s):  
Laser Cooling ◽  
Yttrium Aluminum Garnet ◽  
Cooling Efficiency ◽  
Yttrium Aluminum ◽  
Anti Stokes

scholarly journals Laser cooling of ytterbium-doped silica glass

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Esmaeil Mobini ◽  
Saeid Rostami ◽  
Mostafa Peysokhan ◽  
Alexander Albrecht ◽  
Stefan Kuhn ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
Laser Cooling ◽  
Silica Glass ◽  
Radiative Decay ◽  
Laser Wavelength ◽  
Solid State Laser ◽  
Cooling Efficiency ◽  
Laser Applications ◽  
Anti Stokes ◽  
Rare Earth Doped

Abstract Laser cooling of a solid is achieved when a coherent laser illuminates the material in the red tail of its absorption spectrum, and the heat is carried out by anti-Stokes fluorescence of the blue-shifted photons. Solid-state laser cooling has been successfully demonstrated in several materials, including rare-earth-doped crystals and glasses. Here we show the net cooling of high-purity Yb-doped silica glass samples that are fabricated with low impurities to reduce their parasitic background loss for fiber laser applications. The non-radiative decay rate of the excited state in Yb ions is very small in these glasses due to the low level of impurities, resulting in near-unity quantum efficiency. We report the measurement of the cooling efficiency as a function of the laser wavelength, from which the quantum efficiency of the Yb-doped silica is calculated.

Yag Single Crystals for Scintillators of Stem

1990 ◽  
Vol 48 (1) ◽  
pp. 166-167
Author(s):  
M. Hibino ◽  
K. Irie ◽  
R. Autrata ◽  
P. schauer
Keyword(s):  
Single Crystals ◽  
Yttrium Aluminum Garnet ◽  
Light Guide ◽  
Detection System ◽  
Polished Surface ◽  
Detective Quantum Efficiency ◽  
Backscattered Electrons ◽  
Electron Detection ◽  
Yttrium Aluminum ◽  
Phosphor Screens

Although powdered phosphor screens are usually used for scintillators of STEM, it has been found that the phosphor screen of appropriate thickness should be used depending on the accelerating voltage, in order to keep high detective quantum efficiency. 1 It has been also found that the variation in sensitivity, due to granularity of phosphor screens, makes the measurement of fine electron probe difficult and that the sensitivity reduces with electron irradiation specially at high voltages.In order to find out a preferable scintillator for STEM, single crystals of YAG (yttrium aluminum garnet), which are used for detecting secondary and backscattered electrons in SEM were investigated and compared with powdered phosphor screens, at the accelerating voltages of 100kV and 1 MV. A conventional electron detection system, consisting of scintillator, light guide and PMT (Hamamatsu Photonics R268) was used for measurements. Scintillators used are YAG single crystals of 1.0 to 3.2mm thicknesses (with surfaces matted for good interface to the light guide) and of 0.8mm thickness (with polished surface), and powdered P-46 phosphor screens of 0.07mm and 1.0mm thicknesses for 100kV and 1MV, respectively. Surfaces on electron-incidence side of all scintillators are coated with reflecting layers.

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