Laser cooling of a nanomechanical oscillator into its quantum ground state

TL;DR

This paper demonstrates laser cooling of a silicon nanobeam's mechanical mode from 20K to near its quantum ground state, achieving a phonon occupancy below one using radiation pressure.

Contribution

It reports the first experimental cooling of a nanomechanical oscillator into its quantum ground state via optical radiation pressure at cryogenic temperatures.

Findings

Final phonon occupancy of 0.85 ± 0.04 achieved

Mechanical mode cooled from 20K to near ground state

Supports co-localized acoustic and optical resonances

Abstract

A patterned Si nanobeam is formed which supports co-localized acoustic and optical resonances that are coupled via radiation pressure. Starting from a bath temperature of T=20K, the 3.68GHz nanomechanical mode is cooled into its quantum mechanical ground state utilizing optical radiation pressure. The mechanical mode displacement fluctuations, imprinted on the transmitted cooling laser beam, indicate that a final phonon mode occupancy of 0.85 +-0.04 is obtained.