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基于微球腔增强效应的Yb3+:ZBLANP玻璃材料的激光制冷

Laser Cooling of Yb3+ Doped ZBLANP Glass Based on Microcavity Enhanced Effect

【作者】 焦秀娟

【导师】 印建平;

【作者基本信息】 华东师范大学 , 光学, 2011, 硕士

【摘要】 Pringsheim在1929年首次提出了固体材料反斯托克斯荧光制冷的理论。1946年Purcell第‘次阐述了腔内原子自发辐射荧光与腔模共振时,有增强荧光自发辐射率的现象。1995年,美国Los Alamos国家实验室的Epstein等人对掺杂Yb3+ ZBLANP实现激光冷却(0.3K的降温)。由于在此基础上制作的激光制冷器体积和重量比较小,无噪声污染,因此在光存储领域、电子工业领域都有很好的应用前景。现在国际上有几个小组都在从事固体材料激光制冷的研究工作。例如,美国的Los Alamos的Epstein小组和新墨西哥大学的Sheik-Bahae小组,亚利桑那大学Binder小组,密歇根大学Kaviany小组,约翰霍普金斯大学Jacob B Khurgin小组,西班牙Fernandez小组,他们对固体材料的激光制冷做出了很大贡献,并在不同基质上实现了掺杂Yb3+材料的激光制冷。反斯托克斯荧光制冷是一种很有潜力的制冷方法,但是由于几乎所有的制冷材料对泵浦光的吸收很弱,因而有效提高对泵浦光的吸收从而提高其制冷效率将是一个值得探讨的问题。由于微腔效应,在微型光学腔内的原子受到激光泵浦后其辐射荧光强度取决于荧光波长是否与腔模共振。理论上来说,腔的维数越大,荧光辐射强度越明显。因此我们提出了利用球体的腔效应增强制冷材料对泵浦光的吸收从而提高材料的制冷功率的新方案。微球腔是一个三维全封闭腔,具有很高的对称性,而且本身就是一个光学谐振腔,因此利用微球型材料自身腔效应可有效提高泵浦光的吸收从而增强自发辐射率,进而提高材料的制冷效率。掺杂Yb3+:ZBLAN玻璃在固体材料激光制冷方面有非常详细的理论和实验研究,此外,该材料在实验上已经实现的最大温降达95K,并很有可能作为固体光学冰箱的首选材料。因此本文以掺杂Yb3+:ZBLANP玻璃微球为例,利用球微腔效应对其进行激光制冷的相关理论研究,这对提高制冷材料的制冷功率和光学冰箱的实用性发展有着重要的意义.

【Abstract】 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.

  • 【分类号】TN249
  • 【下载频次】62
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