Laser Cooling Of Yb³⁺ Doped ZBLANP Glass Based On Microcavity Enhanced Effect

In 1929, Pringsheim proposed an idea to realize laser cooling of solid materials based on the anti-Stokes fluorescence at the first time. In 1946, Purcell first elaborated that the spontaneous emission rate can be enhanced if the atom placed inside a cavity is resonant with one of the cavity modes. In 1995, American (United States) Los Alamos national laboratory's Epstein et al realized the cooling of Yb3+-doped ZBLANP glass (the 0.3K temperature decrease). Because this refrigerator based on the laser cooling has quite little volume and the weight, non-noise pollution, therefore it has the very good application prospect in the optical memory and the electronics industry field. Now several internal groups have engaged in the laser cooling of solid material. For example, the US Los Alamos Epstein group and the New Mexico University's Sheik-Bahae group, the University Arizona's Binder group, the Michigan University's Kaviany group, John Hopkins University's Jacob B Khurgin group and Spanish's Fernandez group. They have contributed much to the laser cooling of solid material and achieved laser cooling on different materials doped Yb3+ ion.The anti-Stokes laser cooling is a potential refrigeration method. Because nearly all the refrigeration materials have very little absorption to the pump light, therefore effective enhancement of absorption of pumping light, will thus raise its laser cooling efficiency and this question will be worth discussing very much. As a result of the microcavity effect, the fluorescence intensity is due to resonance of fluorescence with the cavity modes. In theory, the cavity dimension is bigger, the fluorescence is more greatly enhanced. Therefore we proposed a new scheme that making using of the microcavity effect enhance the pumping light absorption. The microsphere cavity is a three dimensional cavity, has a high symmetry, moreover is an optical resonator, therefore may enhances the absorption of pumping light and the spontaneous emission rate. Now people have very detailed theoretical and the experimental study on Yb3+:ZBLAN glass. In addition, the biggest temperature drop which already realized at the experiment reaches 95K and this material has the possibility of optics refrigerator's first choice material. This article takes Yb3+:ZBLAN glass microspheres as an example, has conducted theoretical research. This has vital significance to enhance refrigeration efficiency of material and the development of optics refrigerator.