Amplitude Noise Squeezing in Cavity-Driven Oscillations of a Mechanical Resonator

TL;DR

This paper investigates how cavity-driven oscillations in a mechanical resonator can reduce amplitude noise and produce sub-Poissonian states, with implications for precision measurements and quantum state control.

Contribution

It provides a detailed analysis of amplitude and phase noise in limit-cycle oscillations, revealing noise reduction mechanisms and linewidth narrowing effects in cavity-coupled mechanical resonators.

Findings

Limit-cycle oscillations exhibit lower amplitude noise than harmonic states at the same amplitude.

Sub-Poissonian resonator states can be achieved at low thermal noise levels.

Linewidth narrowing is influenced by phase diffusion and optical spring effects.

Abstract

We analyze the amplitude and phase noise of limit-cycle oscillations in a mechanical resonator coupled parametrically to an optical cavity driven above its resonant frequency. At a given temperature the limit-cycle oscillations have lower amplitude noise than states of the same average amplitude excited by a pure harmonic drive; for sufficiently low thermal noise a sub-Poissonian resonator state can be produced. We also calculate the linewidth narrowing that occurs in the limit-cycle states, and show that while the minimum is set by direct phase diffusion, diffusion due to the optical spring effect can dominate if the cavity is not driven exactly at a side-band resonance.