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A 6-cm Cryogenic Silicon Cavity at 4 K with Crystalline AlGaAs Coatings

POSTER

Abstract

Advancements in ultra-stable lasers locked to cryogenic resonators have enabled the rapid characterization of optical lattice clocks [1] and aided in setting new limits in tabletop investigations of fundamental physics [2]. The performance of these ultra-stable laser systems is fundamentally limited by Brownian thermal noise. For cryogenic cavities, the Brownian noise of the optical mirror coatings is the primary limitation, so characterizing coatings with low mechanical loss is an important step towards building narrower-linewidth lasers. We have developed a 6-cm single-crystal silicon cavity at 4 K with Al0.92Ga0.08As/GaAs crystalline mirror coatings [3]. We expect a fractional frequency instability of 1.3 x 10-17, a 5-fold improvement over an equivalent cavity geometry with dielectric coatings [4]. Frequency noise associated with the large birefringent mode splitting of these crystalline mirror coatings is identified [5]. We employ dual-tone probing of the two polarization eigenmodes of the cavity to cancel this birefringent noise. We present recent improvements to this ultra-stable laser system and investigations into the character of this observed birefringent noise.

[1] Oelker et al., Nat. Photonics 13, 714-719 (2019).

[2] Kennedy et al., Phys. Rev. Lett. 125 201302 (2020).

[3] Cole et al., Optica 3, 647-656 (2016).

[4] Robinson et al., Optica 6, 240-243 (2019).

[5] Yu et al., IEEE EFTF-IFCS, July 7-17 (2021).

Presenters

  • Alexander Staron

    JILA, NIST, and University of Colorado, 440 UCB, Boulder, Colorado 80309, USA, University of Colorado, Boulder

Authors

  • Alexander Staron

    JILA, NIST, and University of Colorado, 440 UCB, Boulder, Colorado 80309, USA, University of Colorado, Boulder

  • Dhruv Kedar

    JILA, NIST, and University of Colorado, 440 UCB, Boulder, Colorado 80309, USA, University of Colorado, Boulder, JILA, NIST and Dept. of Physics, University of Colorado Boulder

  • Eric Oelker

    Institute for Gravitational Research, School of Physics and Astronomy, Glasgow G12 8QQ, United Kingdom, University of Colorado, Boulder, NIST

  • William R Milner

    JILA, NIST, and University of Colorado, 440 UCB, Boulder, Colorado 80309, USA, JILA

  • John M Robinson

    JILA, NIST, and University of Colorado, 440 UCB, Boulder, Colorado 80309, USA, JILA, NIST, and University of Colorado Boulder, University of Colorado, Boulder

  • Jun Ye

    University of Colorado, Boulder, JILA, NIST, and University of Colorado, 440 UCB, Boulder, Colorado 80309, USA, JILA, NIST and Dept. of Physics, University of Colorado Boulder, CU Boulder

  • Jialiang Yu

    Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany

  • Thomas Legero

    Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany

  • Daniele Nicolodi

    Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany, Physikalisch-Technische Bundesanstalt (PTB)

  • Fritz W Riehle

    Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany

  • Uwe Sterr

    Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany