Frequency stability of cryogenic silicon cavities with semiconductor crystalline coatings

authored by
Dhruv Kedar, Jialiang Yu, Eric Oelker, Alexander Staron, William R. Milner, John M. Robinson, Thomas Legero, Fritz Riehle, Uwe Sterr, Jun Ye
Abstract

State-of-the-art optical oscillators employing cryogenic reference cavities are limited in performance by the Brownian thermal noise associated with the mechanical dissipation of the mirror coatings.Recently, crystalline Al1-xGaxAs=GaAs coatings have emerged as a promising candidate for improved coating thermal noise.We present measurements of the frequency noise of two fully crystalline cryogenic reference cavities with Al0.92Ga0.08As=GaAs optical coatings. We report on birefringent noise associated with anticorrelated frequency fluctuations between the polarization modes of the crystalline coatings and identify variables that affect its magnitude. Comparing the birefringent noise between the two cryogenic reference cavities reveals a phenomenological set of scalings with intracavity power and mode area. We implement an interrogation scheme that cancels this noise by simultaneous probing of both polarization modes. The residual noise remaining after this cancellation is larger than both cavities' thermal noise limits but still lower than the instabilities previously measured on equivalent resonators with dielectric coatings. Though the source of these noise mechanisms is unclear, we demonstrate that crystalline coatings can provide stability and sensitivity competitive with resonators employing dielectric coatings.

External Organisation(s)
JILA
National Metrology Institute of Germany (PTB)
University of Glasgow
Type
Article
Journal
OPTICA
Volume
10
Pages
464-470
No. of pages
7
ISSN
2334-2536
Publication date
20.04.2023
Publication status
Published
Peer reviewed
Yes
ASJC Scopus subject areas
Electronic, Optical and Magnetic Materials, Atomic and Molecular Physics, and Optics
Electronic version(s)
https://doi.org/10.1364/OPTICA.479462 (Access: Open)