Optical cavity cooling of mechanical modes of a semiconductor nanomenbrane

TY - JOUR

T1 - Optical cavity cooling of mechanical modes of a semiconductor nanomenbrane

AU - Usami, Koji

AU - Rasmussen, Andreas Næsby

AU - Bagci, Tolga

AU - Nielsen, Bo Melholt

AU - Stobbe, Søren

AU - Liu, J.

AU - Lodahl, Peter

AU - Polzik, Eugene Simon

PY - 2012/2

Y1 - 2012/2

N2 - Mechanical oscillators can be optically cooled using a technique known as optical-cavity back-action. Cooling of composite metal-semiconductor mirrors, dielectric mirrors and dielectric membranes has been demonstrated. Here we report cavity cooling of mechanical modes in a high-quality-factor and optically active semiconductor nanomembrane. The cooling is a result of electron-hole generation by cavity photons. Consequently, the cooling factor depends on the optical wavelength, varies drastically in the vicinity of the semiconductor bandgap, and follows the excitonic absorption behaviour. The resultant photo-induced rigidity is large and a mode temperature cooled from room temperature down to 4ĝ€‰K is realized with 50ĝ€‰1/4W of light and a cavity finesse of just 10. Thermal stress due to non-radiative relaxation of the electron-hole pairs is the primary cause of the cooling. We also analyse an alternative cooling mechanism that is a result of electronic stress via the deformation potential, and outline future directions for cavity optomechanics with optically active semiconductors.

AB - Mechanical oscillators can be optically cooled using a technique known as optical-cavity back-action. Cooling of composite metal-semiconductor mirrors, dielectric mirrors and dielectric membranes has been demonstrated. Here we report cavity cooling of mechanical modes in a high-quality-factor and optically active semiconductor nanomembrane. The cooling is a result of electron-hole generation by cavity photons. Consequently, the cooling factor depends on the optical wavelength, varies drastically in the vicinity of the semiconductor bandgap, and follows the excitonic absorption behaviour. The resultant photo-induced rigidity is large and a mode temperature cooled from room temperature down to 4ĝ€‰K is realized with 50ĝ€‰1/4W of light and a cavity finesse of just 10. Thermal stress due to non-radiative relaxation of the electron-hole pairs is the primary cause of the cooling. We also analyse an alternative cooling mechanism that is a result of electronic stress via the deformation potential, and outline future directions for cavity optomechanics with optically active semiconductors.

U2 - 10.1038/nphys2196

DO - 10.1038/nphys2196

M3 - Journal article

SN - 1745-2473

VL - 8

SP - 168

EP - 172

JO - Nature Physics

JF - Nature Physics

IS - 2

ER -