Hehlen Markus P, Meng Junwei, Albrecht Alexander R, Lee Eric R, Gragossian Aram, Love Steven P, Hamilton Christopher E, Epstein Richard I, Sheik-Bahae Mansoor
1Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 USA.
2Department of Physics & Astronomy, University of New Mexico, Albuquerque, NM 87131 USA.
Light Sci Appl. 2018 Jun 6;7:15. doi: 10.1038/s41377-018-0028-7. eCollection 2018.
Solid-state optical refrigeration uses anti-Stokes fluorescence to cool macroscopic objects to cryogenic temperatures without vibrations. Crystals such as Yb-doped YLiF (YLF:Yb) have previously been laser-cooled to 91 K. In this study, we show for the first time laser cooling of a payload connected to a cooling crystal. A YLF:Yb crystal was placed inside a Herriott cell and pumped with a 1020-nm laser (47 W) to cool a HgCdTe sensor that is part of a working Fourier Transform Infrared (FTIR) spectrometer to 135 K. This first demonstration of an all-solid-state optical cryocooler was enabled by careful control of the various desired and undesired heat flows. Fluorescence heating of the payload was minimized by using a single-kink YLF thermal link between the YLF:Yb cooling crystal and the copper coldfinger that held the HgCdTe sensor. The adhesive-free bond between YLF and YLF:Yb showed excellent thermal reliability. This laser-cooled assembly was then supported by silica aerogel cylinders inside a vacuum clamshell to minimize undesired conductive and radiative heat loads from the warm surroundings. Our structure can serve as a baseline for future optical cryocooler devices.
固态光制冷利用反斯托克斯荧光将宏观物体冷却至低温，且无振动。此前，诸如掺镱的钇锂氟化物（YLF:Yb）等晶体已被激光冷却至91 K。在本研究中，我们首次展示了对与冷却晶体相连的负载进行激光冷却。将一块YLF:Yb晶体置于赫里奥特池内，并用1020纳米激光（47瓦）泵浦，以将作为工作傅里叶变换红外（FTIR）光谱仪一部分的碲镉汞传感器冷却至135 K。通过仔细控制各种期望和不期望的热流，实现了全固态光制冷器的首次演示。通过在YLF:Yb冷却晶体和固定碲镉汞传感器的铜冷指之间使用单扭结YLF热链路，可以将负载的荧光加热降至最低。YLF与YLF:Yb之间的无粘合剂键合显示出优异的热可靠性。然后，在真空翻盖内用二氧化硅气凝胶圆柱体支撑这个激光冷却组件，以尽量减少来自温暖环境的不期望的传导和辐射热负荷。我们的结构可为未来的光制冷器装置提供一个基线。
