Ahlefeldt R L, Hush M R, Sellars M J
Department of Physics, Montana State University, Bozeman, Montana 59717, USA.
Laser Physics Centre, Research School of Physics and Engineering, The Australian National University, Canberra 0200, Australia.
Phys Rev Lett. 2016 Dec 16;117(25):250504. doi: 10.1103/PhysRevLett.117.250504. Epub 2016 Dec 15.
We obtain a low optical inhomogeneous linewidth of 25 MHz in the stoichiometric rare-earth crystal EuCl_{3}·6H_{2}O by isotopically purifying the crystal in ^{35}Cl. With this linewidth, an important limit for stoichiometric rare-earth crystals is surpassed: the hyperfine structure of ^{153}Eu is spectrally resolved, allowing the whole population of ^{153}Eu^{3+} ions to be prepared in the same hyperfine state using hole-burning techniques. This material also has a very high optical density, and can have long coherence times when deuterated. This combination of properties offers new prospects for quantum information applications. We consider two of these: quantum memories and quantum many-body studies. We detail the improvements in the performance of current memory protocols possible in these high optical depth crystals, and describe how certain memory protocols, such as off-resonant Raman memories, can be implemented for the first time in a solid-state system. We explain how the strong excitation-induced interactions observed in this material resemble those seen in Rydberg systems, and describe how these interactions can lead to quantum many-body states that could be observed using standard optical spectroscopy techniques.
通过对化学计量比的稀土晶体EuCl₃·6H₂O进行³⁵Cl同位素纯化，我们在其中获得了25MHz的低光学非均匀线宽。凭借这一线宽，超越了化学计量比稀土晶体的一个重要限制：¹⁵³Eu的超精细结构在光谱上得以分辨，这使得利用烧孔技术能够将¹⁵³Eu³⁺离子的整个布居制备在相同的超精细态。这种材料还具有非常高的光密度，并且在氘化后可以有较长的相干时间。这些特性的组合为量子信息应用提供了新的前景。我们考虑其中的两个应用：量子存储器和量子多体研究。我们详细阐述了在这些高光深度晶体中当前存储协议性能可能的改进，并描述了某些存储协议，如非共振拉曼存储器，如何能够首次在固态系统中实现。我们解释了在这种材料中观察到的强激发诱导相互作用如何类似于在里德堡系统中看到的相互作用，并描述了这些相互作用如何导致可以使用标准光学光谱技术观察到的量子多体态。
