TY - JOUR
AU - Dhruv Kedar
AU - Jialiang Yu
AU - Eric Oelker
AU - Alexander Staron
AU - William Milner
AU - John Robinson
AU - Thomas Legero
AU - Fritz Riehle
AU - Uwe Sterr
AU - Jun Ye
AB - <jats:p>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 Al<jats:sub>1−<jats:italic>x</jats:italic></jats:sub>Ga<jats:sub> <jats:italic>x</jats:italic> </jats:sub>As/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 Al<jats:sub>0.92</jats:sub>Ga<jats:sub>0.08</jats:sub>As/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.</jats:p>
BT - Optica
DA - 2023-04
DO - 10.1364/optica.479462
IS - 4
N2 - <jats:p>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 Al<jats:sub>1−<jats:italic>x</jats:italic></jats:sub>Ga<jats:sub> <jats:italic>x</jats:italic> </jats:sub>As/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 Al<jats:sub>0.92</jats:sub>Ga<jats:sub>0.08</jats:sub>As/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.</jats:p>
PY - 2023
EP - 464
T2 - Optica
TI - Frequency stability of cryogenic silicon cavities with semiconductor crystalline coatings
UR - https://opg.optica.org/optica/fulltext.cfm?uri=optica-10-4-464&id=528812
VL - 10
SN - 2334-2536
ER -