Near-field Levitated Quantum Optomechanics with Nanodiamonds

TL;DR

This paper proposes a theoretical method for near-field optical levitation of nanodiamonds with embedded quantum emitters, enhancing optomechanical coupling and enabling room-temperature quantum experiments.

Contribution

It introduces a novel approach using quantum emitter ensembles to achieve optical levitation via repulsive near-field forces, improving optomechanical system performance.

Findings

Quantum emitter ensembles can increase polarizability beyond bulk material.

Near-field levitation enables stronger optomechanical coupling.

Potential for room-temperature quantum optomechanics with nanodiamonds.

Abstract

We theoretically show that the dipole force of an ensemble of quantum emitters embedded in a dielectric nanosphere can be exploited to achieve near-field optical levitation. The key ingredient is that the polarizability from the ensemble of embedded quantum emitters can be larger than the bulk polarizability of the sphere, thereby enabling the use of repulsive optical potentials and consequently the levitation using optical near-fields. In levitated cavity quantum optomechanics, this could be used to boost the single-photon coupling by combining larger polarizability to mass ratio, larger field gradients, and smaller cavity volumes while remaining in the resolved sideband regime and at room temperature. A case study is done with a nanodiamond containing a high-density of silicon-vacancy color centers that is optically levitated in the evanescent field of a tappered nano-fiber and coupled to a high-finesse microsphere cavity.