In:
Laser & Photonics Reviews, Wiley, Vol. 15, No. 10 ( 2021-10)
Abstract:
The hydrothermal synthesis and characterization of 10%Yb 3+ :LiLuF 4 (LLF) microcrystals are reported. A combination of X‐ray diffraction (XRD) analysis, analytical transmission electron microscopy (TEM), scanning TEM (STEM), energy‐dispersive X‐ray (EDX) spectroscopy), temperature‐dependent Fourier‐transform infrared (FTIR) spectroscopy, and photoluminescence (PL) measurements confirm a scheelite ( I 4 1 / a ) phase and substitutional doping of Yb 3+ within the microcrystals. Laser cooling to more than 20 K below room temperature in vacuum (10 −3 torr) is demonstrated when irradiating individual microcrystals using a near‐infrared pumping wavelength ( λ = 1020nm) at a laser power of 40 mW (irradiance of 0.85 MW cm −2 ). The use of these microcrystals is further demonstrated for solid‐state laser refrigeration of an electron‐transparent silicon‐nitride (Si 3 N 4 ) TEM window. A combination of internal luminescence thermometry, heat‐transfer modeling, and control measurements on lithographically patterned Si 3 N 4 optical cavities is used to demonstrate successful bulk laser cooling of Si 3 N 4 TEM windows by ≈15 K below room temperature, opening new opportunities for contactless in situ TEM refrigeration.
Type of Medium:
Online Resource
ISSN:
1863-8880
,
1863-8899
DOI:
10.1002/lpor.202100019
Language:
English
Publisher:
Wiley
Publication Date:
2021
detail.hit.zdb_id:
2266512-2
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