Optical coherence and energy-level properties of a Tm³⁺-doped LiNbO₃ waveguide at subkelvin temperatures
We characterize the optical coherence and energy-level properties of the 795-nm ³H₆ to ³H₄ transition of Tm³⁺ in a Ti⁴⁺:LiNbO₃ waveguide at temperatures as low as 0.65 K. Coherence properties are measured with varied temperature, magnetic field, optical excitation power and wavelength, and measurement timescale. We also investigate nuclear spin-induced hyperfine structure and population dynamics with varying magnetic field and laser excitation power. Except for accountable differences due to different Ti⁴⁺- and Tm³⁺-doping concentrations, we find that the properties of Tm³⁺:Ti⁴⁺:LiNbO₃ produced by indiffusion doping are consistent with those of a bulk-doped Tm³⁺:LiNbO₃ crystal measured under similar conditions. Our results, which complement previous work in a narrower parameter space, support using rare-earth ions for integrated optical and quantum signal processing.
© 2021 American Physical Society. Received 21 January 2021; revised 24 March 2021; accepted 24 March 2021; published 12 April 2021. We thank M. George, R. Ricken and W. Sohler for fabricating the waveguide, and to M. Hedges, H. Mallahzadeh, T. Lutz, L. Veissier, C. Deshmukh, and M. Falamarzi Askarani for discussions. We acknowledge funding through the Natural Sciences and Engineering Research Council of Canada (NSERC), Alberta Ministry for Jobs, Economy and Innovation's Major Innovation Fund on Quantum Technology, Alberta Innovates Technology Futures (AITF) research program, Defense Advanced Research Projects Agency (DARPA) Quiness program (Contract No. W31P4Q-13-1-0004), National Science Foundation (NSF) under Awards No. PHY-1415628 and No. CHE-1416454, NSF Science and Technology Center for Integrated Quantum Materials under Cooperative Agreement No. DMR-1231319, Department of Energy/High Energy Physics QuantISED program grant, QCCFP (Quantum Communication Channels for Fundamental Physics), Award No. DE-SC0019219, AQT Intelligent Quantum Networks and Technologies (INQNET) research program, and the Dutch Research Council (NWO).
Accepted Version - 2101.08863.pdf
Published - PhysRevB.103.134105.pdf