Optical levitation of high purity nanodiamonds in vacuum without heating

TL;DR

This paper demonstrates that milling pure nanodiamonds prevents heating at high optical intensities, enabling stable optical levitation in high vacuum without temperature constraints, advancing quantum experiments with nanodiamonds.

Contribution

The study introduces a method to produce nanodiamonds that do not heat under intense optical trapping, allowing higher vacuum levels in levitation experiments.

Findings

Nanodiamonds do not heat up above 700 GW/m$^2$ at pressures below 5 mbar.

Heating limitations in optical levitation are overcome with milled pure nanodiamonds.

Stable levitation in high vacuum without heating constraints is now feasible.

Abstract

Levitated nanodiamonds containing nitrogen vacancy centres in high vacuum are a potential test bed for numerous phenomena in fundamental physics. However, experiments so far have been limited to low vacuum due to heating arising from optical absorption of the trapping laser. We show that milling pure diamond creates nanodiamonds that do not heat up as the optical intensity is raised above 700 GW/m$^2$ below 5 mbar of pressure. This advance now means that the level of attainable vacuum for nanodiamonds in optical dipole traps is no longer temperature limited.