Squeezing of light via reflection from a silicon micromechanical resonator

TL;DR

This paper demonstrates the generation of squeezed light using a silicon micromechanical resonator coupled to a nanophotonic cavity, revealing quantum radiation pressure effects despite thermal noise.

Contribution

It reports the first observation of light squeezing via reflection from a silicon micromechanical resonator in an integrated optomechanical system.

Findings

Achieved 4.5% squeezing below shot-noise level.

Observed squeezing at a 28 MHz mechanical resonance frequency.

Demonstrated quantum radiation pressure effects in a thermal state.

Abstract

We present the measurement of squeezed light generation using an engineered optomechanical system fabricated from a silicon microchip and composed of a micromechanical resonator coupled to a nanophotonic cavity. Laser light is used to measure the fluctuations in the position of the mechanical resonator at a measurement rate comparable to the free dynamics of the mechanical resonator, and greater than its thermal decoherence rate. By approaching the strong continuous measurement regime we observe, through homodyne detection, non-trivial modifications of the reflected light's vacuum fluctuation spectrum. In spite of the mechanical resonator's highly excited thermal state ($10,000$ phonons), we observe squeezing at the level of $4.5 \pm 0.5%$ below that of shot-noise over a few MHz bandwidth around the mechanical resonance frequency of 28 MHz. This squeezing is interpreted as an unambiguous quantum signature of radiation pressure shot-noise.