Optoelectronic cooling of mechanical modes in a semiconductor nanomembrane

TL;DR

This paper demonstrates a novel optoelectronic cooling mechanism for semiconductor membranes, achieving significant cooling of mechanical modes from room temperature using minimal light power, with potential applications in photonics and spintronics.

Contribution

It introduces a new optoelectronic cavity cooling method based on deformation potential coupling in semiconductor membranes, differing from previous thermal or radiation pressure techniques.

Findings

Achieved cooling of a mechanical mode to 4 K from room temperature.

Used only 50 μW of light with a cavity finesse of 10.

Demonstrated efficient cooling via photo-induced electron-hole pairs.

Abstract

Optical cavity cooling of mechanical resonators has recently become a research frontier. The cooling has been realized with a metal-coated silicon microlever via photo-thermal force and subsequently with dielectric objects via radiation pressure. Here we report cavity cooling with a crystalline semiconductor membrane via a new mechanism, in which the cooling force arises from the interaction between the photo-induced electron-hole pairs and the mechanical modes through the deformation potential coupling. The optoelectronic mechanism is so efficient as to cool a mode down to 4 K from room temperature with just 50 uW of light and a cavity with a finesse of 10 consisting of a standard mirror and the sub-wavelength-thick semiconductor membrane itself. The laser-cooled narrow-band phonon bath realized with semiconductor mechanical resonators may open up a new avenue for photonics and spintronics devices.