Georg A Raithel is inviting you to a scheduled Zoom meeting.
Topic: Remy Legaie seminar
Time: Oct 5, 2021 03:45 PM Eastern Time (US and Canada) Join Zoom Meeting
https://umich.zoom.us/j/93856929175 Meeting ID: 938 5692 9175
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Neutral atoms provide an excellent resource for quantum information processing, combining the long atomic coherence times of the hyperfine ground-state with strong dipole-dipole interactions of highly excited Rydberg states for generating deterministic entanglement between qubits separated by < 10 µm [1].

For robust Rydberg excitation of atomic qubits for gate operations, the two-photon excitation must be detuned from the intermediate excited state to avoid losses due to spontaneous emission. High fidelity gates also require narrow linewidth excitation lasers with excellent long term frequency stability. These requirements can be met using lasers stabilized to a high-finesse optical cavity, exploiting techniques developed for lasers on state-of-the-art optical lattice clocks. Recently, details of cavity stabilized lasers systems for Rydberg excitation of K, Rb, and Sr atoms have been presented, achieving typical linewidths around 1-10 kHz.

In this talk, I will present the construction and characterization of three continuous wave (CW) sub-kHz linewidth lasers stabilized simultaneously to an ultra-high finesse Fabry-Perot cavity made of ultra-low expansion (ULE) glass, with tunable offset-lock frequency [2]. Furthermore, high-resolution electromagnetically induced transparency (EIT) spectroscopy of cold Cs Rydberg states is used to calibrate the cavity mode frequencies with respect to Rydberg transitions and determine the cavity long term drift of ∼ 1 Hz/s. These measurement are competitive against doubly-stabilized optical clocks and offer an order of magnitude improvement compared to similar cavity stabilized Rydberg laser systems.

[1] M. Saffman, T. Walker, and K. Mølmer, Rev. Mod. Phys. 82, 2313 (2010).
[2] R. Legaie et al., J. Opt. Soc. Am. B 35, 892 (2018).

Remy Legaie obtained his PhD in Physics from the University of Strathclyde (Glasgow, Scotland) in 2019, focusing on quantum information processing with ultra-cold Rydberg atoms. He then held a first postdoctoral position at CNRS (Marseille, France) in optical frequency metrology using laser cooled trapped ions. At the beginning of 2021, he was recruited at ENS Paris-Saclay (Paris, France) for a second postdoctoral position, in charge of developing a new experiment using Rydberg atoms in vapor cell as radio frequency field sensor.