Year: 2020
Type: article
Abstract: We present a joint theoretical and experimental analysis of thermorefractive noise in high-quality-factor (Q), small-mode-volume (V) optical microcavities.Analogous to well-studied stability limits imposed by Brownian motion in macroscopic Fabry-Perot resonators, we show that microcavity thermorefractive noise gives rise to a mode-volume-dependent maximum effective quality factor.State-of-the-art fabricated microcavities are found to be within one order of magnitude of this bound.By measuring the first thermodynamically limited frequency noise spectra of wavelength-scale high-Q=V silicon photonic crystal cavities, we confirm the assumptions of our theory, demonstrate a broadband sub-μK= ffiffiffiffiffiffi Hz p temperature sensitivity, and unveil a new technique for discerning subwavelength changes in microcavity mode volumes.To illustrate the immediate implications of these results, we show that thermorefractive noise limits the optimal performance of recently proposed room-temperature, all-optical qubits using cavityenhanced bulk material nonlinearities.Looking forward, we propose and analyze coherent thermo-optic noise cancellation as one potential avenue toward violating these bounds, thereby enabling continued development in quantum optical measurement, precision sensing, and low-noise integrated photonics.
Source: Physical Review X
Institutions: Massachusetts Institute of Technology, NTT (United States)
Language: English
Topic: Photonic and Optical Devices
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,200
OpenAlex ID: W3021489029