arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2109.02702physics.opticscond-mat.mtrl-sci
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固体激光冷却的自适应四级模型

Adaptive four-level modeling of laser cooling of solids

Weiliang Jin, Cheng Guo, Meir Orenstein, Shanhui Fan

摘要:

稀土掺杂固体的激光冷却已经在广泛的材料平台上得到了证实,激发了简单的唯象模型的发展,如四能级模型,以阐明激光冷却在各种操作条件下的普遍性质。然而,这些模型通常需要输入的全吸收光谱,必须提供实验或额外的复杂的原子建模。在这封信中,我们建议,一个四能级模型,当扩展到承认有效的能级自适应的泵浦光子能量,可以准确地预测作为温度和泵浦频率的函数,使用只有很少的输入,如在一个单一的频率和温度下测量的吸收系数的冷却效率。我们的模型利用稀土离子激发的准平衡性质来确定有效的四个能级。该模型是有效的,对出版的实验结果的跨度的材料,包括镱/铥掺杂的玻璃和晶体。利用验证后的模型,导出了最佳泵浦频率和工作带宽的显式表达式。该模型大大简化了激光冷却的建模过程,有望促进光学制冷的进一步发展。

英文摘要:

Laser cooling of rare-earth doped solids has been demonstrated across a wide range of material platforms, inspiring the development of simple phenomenological models such as the four-level model to elucidate the universal properties of laser cooling under various operating conditions. However, these models usually require the input of full absorption spectra that must be provided experimentally or by additional complicated atomic modeling. In this letter, we propose that a four-level model, when extended to admit effective energy levels adaptive to the pumping photon energy, can accurately predict the cooling efficiency as a function of temperature and pumping frequency using only few inputs such as the absorption coefficient measured at a single frequency and temperature. Our model exploits the quasi-equilibrium properties of the excitation of rare-earth ions for the determination of the effective four energy levels. The model is validated against published experimental results for a span of materials including ytterbium/thulium-doped glass and crystals. With the verified model, we derive explicit expressions for the optimal frequency and the operating bandwidth of pumping laser. Our model significantly simplifies the modeling process of laser cooling, and is expected to stimulate further development of optical refrigeration.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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