Dispersive coupling between light and a rare-earth ion doped mechanical resonator

TL;DR

This paper proposes a method to enhance opto-mechanical coupling in rare-earth doped resonators using spectral hole burning and magnetic field gradients, enabling quantum-level observations of mechanical vibrations.

Contribution

It introduces a novel approach combining spectral hole burning and magnetic field gradients to achieve strong dispersive coupling in rare-earth ion systems.

Findings

Spectral hole burning enhances sensitivity to mechanical motion.

Magnetic field gradients improve opto-mechanical coupling strength.

Quantum features like zero point vibrations are observable with this method.

Abstract

By spectrally hole burning an inhomogeneously broadened ensemble of ions while applying a controlled perturbation, one can obtain spectral holes that are functionalized for maximum sensitivity to different perturbations. We propose to use such hole burnt structures for the dispersive optical interaction with rare-earth ion dopants whose frequencies are sensitive to crystal strain due to the bending motion of a crystal cantilever. A quantitative analysis shows that good optical sensitivity to the bending motion is obtained if a magnetic field gradient is applied across the crystal during hole burning, and that the resulting opto-mechanical coupling strength is sufficient for observing quantum features such as zero point vibrations.