Optical trapping of high-aspect-ratio NaYF hexagonal prisms for kHz-MHz gravitational wave detectors

TL;DR

This study demonstrates the optical trapping of high-aspect-ratio NaYF hexagonal prisms in vacuum, highlighting their potential for high-frequency gravitational wave detection due to low heating and high trap frequencies.

Contribution

The paper introduces a novel method for trapping high-aspect-ratio NaYF prisms in vacuum with specific orientation, enabling high trap frequencies suitable for gravitational wave detection.

Findings

Successful trapping of NaYF prisms with characteristic modes

Comparison of motional spectra with numerical simulations

Potential for higher trap frequencies using laser refrigeration

Abstract

We present experimental results on optical trapping of Yb-doped $\beta-$NaYF sub-wavelength-thickness high-aspect-ratio hexagonal prisms with a micron-scale radius. The prisms are trapped in vacuum using an optical standing wave, oriented with the normal vector to their face along the beam propagation direction, and exhibit characteristic modes of three translational and two torsional degrees of freedom. The measured motional spectra are compared with numerical simulations. This plate-like geometry simultaneously enables trapping with low photon-recoil-heating, high mass, and high trap frequency, potentially leading to advances in high frequency gravitational wave searches in the Levitated Sensor Detector (LSD), currently under construction. The material used here has previously been shown to exhibit internal cooling via laser refrigeration when optically trapped and illuminated with light of suitable wavelength. Employing such laser refrigeration methods in the context of our work may enable higher trapping intensity thus and higher trap frequencies for gravitational wave searches approaching the several hundred kHz range.