Prof. Jeff Thompson, Princeton University
Leuchs-Russell Auditorium, A.1.500, Staudtstr. 2

Location details

Abstract:
Individually addressed rare earth ions are a promising platform for quantum information processing. Erbium is particularly attractive as a single photon source and quantum memory for quantum networks, owing to its optical transition at 1.5 µm, in the lowest-loss telecom band. A central challenge to utilizing individual rare earth ions is their low photon emission rates, which results from the dipole-forbidden nature of the intra-4f optical transitions. We have demonstrated a solution to this problem by coupling single Er³⁺ ion dopants in a Y₂SiO₅ crystal to a silicon nanophotonic circuit, where a photonic crystal cavity tuned to the ions’ resonance enhances the emission rate by nearly three orders of magnitude [1]. This has enabled the observation of single-photon emission from single Er³⁺ ions for the first time. More recently, we have leveraged the strong cavity modification of the spontaneous emission to control the spin selection rules, which enables single-shot quantum nondemolition measurement of the ion’s spin with 95% fidelity [2]. We have measured the spin T₁ of single Er³⁺ ions for the first time and find that it exceeds 40 seconds. T₂ reaches 100 µs, limited by the nuclear spin bath, and I will discuss two strategies to mitigate this: dynamical decoupling and control of the spin bath, as well as the development of a new host materials with lower abundance of nuclear spins, such as TiO₂ [3]. I will conclude with prospects for creating arrays of strongly interacting Er³⁺ spins using ion implantation, with sub-wavelength optical addressing using frequency multiplexing. Using this strategy, we have recently demonstrated simultaneous initialization, measurement and control of two ions in a single optical mode [4].

[1]      A. M. Dibos, M. Raha, C. M. Phenicie, and J. D. Thompson, Phys. Rev. Lett. 120, 243601 (2018).
[2]      M. Raha, S. Chen, C. M. Phenicie, S. Ourari, A. M. Dibos, and J. D. Thompson, arxiv 1907.09992 (2019).
[3]      C. M. Phenicie, P. Stevenson, S. Welinski, B. C. Rose, A. T. Asfaw, R. J. Cava, S. A. Lyon, N. P. De Leon, and J. D. Thompson, arxiv 1909.06304 (2019).
[4]      S. Chen, M. Raha, et al, manuscript in preparation (2019).