Ultra-narrow optical inhomogeneous linewidth in a stoichiometric rare earth crystal

• Main Authors: Ahlefeldt, R. L, Hush, M. R, Sellars, M. J
• Format: Journal Article
• Language: English
• Published: 25-07-2016
• Subjects: Physics - Atomic Physics; Physics - Materials Science; Physics - Quantum Physics
• DOI: 10.48550/arxiv.1601.05013

Phys. Rev. Lett. 117, 250504 (2016) We have obtained a low optical inhomogeneous linewidth of 25 MHz in the
stoichiometric rare earth crystal EuCl3 .6H2 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 153Eu is
spectrally resolved, allowing the whole population of 153Eu3+ 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 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.