Optica Publishing Group

Thermal intermodulation noise in cavity-based measurements

Version 2 2020-11-09, 22:19
Version 1 2020-11-09, 22:19
Posted on 2020-11-09 - 22:19
Thermal frequency fluctuations in optical cavities limit the sensitivity of precision experiments ranging from gravitational wave observatories to optical atomic clocks. Conventional modeling of these noises assumes a linear response of the optical field to the fluctuations of cavity frequency. Fundamentally, however, this response is nonlinear. Here we show that nonlinearly transduced thermal fluctuations of cavity frequency can dominate the broadband noise in photodetection, even when the magnitude of fluctuations is much smaller than the cavity linewidth. We term this noise ``thermal intermodulation noise'' and show that for a resonant laser probe it manifests as intensity fluctuations. We report and characterize thermal intermodulation noise in an optomechanical cavity, where the frequency fluctuations are caused by mechanical Brownian motion, and find excellent agreement with our developed theoretical model. We demonstrate that the effect is particularly relevant to quantum optomechanics: using a phononic crystal Si3N4 membrane with a low mass, soft-clamped mechanical mode we are able to operate in the regime where measurement quantum backaction contributes as much force noise as the thermal environment does. However, in the presence of intermodulation noise, quantum signatures of measurement are not revealed in direct photodetectors. The reported noise mechanism, while studied for an optomechanical system, can exist in any optical cavity.


3 Biotech
3D Printing in Medicine
3D Research
3D-Printed Materials and Systems
AAPG Bulletin
AAPS PharmSciTech
Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg
ABI Technik (German)
Academic Medicine
Academic Pediatrics
Academic Psychiatry
Academic Questions
Academy of Management Discoveries
Academy of Management Journal
Academy of Management Learning and Education
Academy of Management Perspectives
Academy of Management Proceedings
Academy of Management Review
Select your citation style and then place your mouse over the citation text to select it.



Usage metrics



Sergey Fedorov
Alberto Beccari
Amirali Arabmoheghi
Dalziel Wilson
Nils Johan Engelsen
Tobias Kippenberg


need help?