Optical self-cooling of a membrane oscillator in a cavity optomechanical experiment at room temperature

TL;DR

This study demonstrates optical self-cooling of a membrane oscillator at room temperature, reducing its effective temperature to a few millikelvin, and discusses the challenges and future prospects for reaching quantum ground state cooling.

Contribution

It shows room-temperature sideband cooling of a membrane oscillator to millikelvin temperatures, highlighting the impact of classical laser noise on cooling limits.

Findings

Achieved effective temperature of a few mK in a room-temperature experiment

Phononic occupation number around 100

Classical laser noise limits further cooling

Abstract

Thermal noise is a major obstacle to observing quantum behavior in macroscopic systems. To mitigate its effect, quantum optomechanical experiments are typically performed in a cryogenic environment. However, this condition represents a considerable complication in the transition from fundamental research to quantum technology applications. It is therefore interesting to explore the possibility of achieving the quantum regime in room temperature experiments. In this work we test the limits of sideband cooling vibration modes of a SiN membrane in a cavity optomechanical experiment. We obtain an effective temperature of a few mK, corresponding to a phononic occupation number of around 100. We show that further cooling is prevented by the excess classical noise of our laser source, and we outline the road toward the achievement of ground state cooling