Noise-Induced Limits on Responsivity and SNR for Nonlinear Exceptional Point Sensing

Fuente: arXiv
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Main Authors: Darcie, Todd, Aitchison, J. Stewart
Format: Preprint
Published: 2025
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author Darcie, Todd
Aitchison, J. Stewart
author_facet Darcie, Todd
Aitchison, J. Stewart
contents Exceptional points (EPs) have been suggested for ultra-sensitive sensing because the eigenfrequency splitting grows as the nth-root of a perturbation, suggesting divergent responsivity. In ideal linear devices, however, this responsivity gain is reconciled by a matching divergence in the quantum shot-noise floor, so the net signal-to-noise ratio remains unchanged. Recent work has extended this argument to nonlinear devices, such as above-threshold lasers, predicting other divergences at an EP that is shifted by the interplay of noise and saturation effects. Here we analyze a system of two coupled saturable resonators and show analytically that a self-consistent treatment of fluctuation dynamics removes these divergences entirely. Islands of instability arise in the parameter space surrounding the EP due to the coupling of phase noise into the amplitude dynamics, dictating a maximum responsivity and maximum noise that can be experimentally observed. Stochastic Langevin simulations of the full nonlinear system corroborate our analytical results down to zero detuning.
format Preprint
id arxiv_https___arxiv_org_abs_2509_20346
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Noise-Induced Limits on Responsivity and SNR for Nonlinear Exceptional Point Sensing
Darcie, Todd
Aitchison, J. Stewart
Optics
Exceptional points (EPs) have been suggested for ultra-sensitive sensing because the eigenfrequency splitting grows as the nth-root of a perturbation, suggesting divergent responsivity. In ideal linear devices, however, this responsivity gain is reconciled by a matching divergence in the quantum shot-noise floor, so the net signal-to-noise ratio remains unchanged. Recent work has extended this argument to nonlinear devices, such as above-threshold lasers, predicting other divergences at an EP that is shifted by the interplay of noise and saturation effects. Here we analyze a system of two coupled saturable resonators and show analytically that a self-consistent treatment of fluctuation dynamics removes these divergences entirely. Islands of instability arise in the parameter space surrounding the EP due to the coupling of phase noise into the amplitude dynamics, dictating a maximum responsivity and maximum noise that can be experimentally observed. Stochastic Langevin simulations of the full nonlinear system corroborate our analytical results down to zero detuning.
title Noise-Induced Limits on Responsivity and SNR for Nonlinear Exceptional Point Sensing
topic Optics
url https://arxiv.org/abs/2509.20346