Rotating fluorescent nanodiamond assemblies with focused Laguerre-Gaussian beams

TL;DR

This paper demonstrates controlled rotation of fluorescent nanodiamond assemblies using structured light with orbital angular momentum, and explores their application in magnetic field measurements via ODMR.

Contribution

It introduces a method to rotate nanodiamond clusters with Laguerre-Gaussian beams and investigates their dynamics and potential for magnetic sensing.

Findings

Assemblies can be rotated at frequencies up to 5 Hz.

Brownian dynamics analyzed through video tracking.

ODMR spectra collected along the orbit reveal insights for magnetic field reconstruction.

Abstract

Optical tweezers which utilize structured light fields enable the rotation of trapped nanoparticles through the transfer of orbital angular momentum (OAM) from holographically generated Laguerre-Gaussian (LG) modes. In this research we use OAM transfer to demonstrate controlled rotation of bright fluorescent nanodiamond clusters assembled in a focused higher-order LG beam. We find that the assemblies can be effectively rotated in a two-dimensional optical trap with orbital frequencies of up to 5 Hz. We use video tracking to explore the Brownian dynamics of such a trapping arrangement and look at the impact of orientation stability on measurements of optically detected magnetic resonance (ODMR) with an applied weak external magnetic field. By collecting ODMR spectra at multiple points along the orbit, we show that the constrained two-dimensional motion can provide additional insights for vector magnetic field reconstruction.