All-optical Saddle Trap

TL;DR

This paper introduces an all-optical saddle trap using superimposed Laguerre-Gauss modes to create a rotating saddle-shaped intensity profile that can stably trap nanoparticles in high vacuum, enabling advanced optomechanics experiments.

Contribution

It demonstrates a novel optical trapping method with a rotating saddle profile capable of stable nanoparticle confinement and analyzes its stability, dynamics, and cooling properties.

Findings

Stable trapping of nanoparticles in high vacuum using the optical saddle.

Analysis of stability conditions and center-of-mass dynamics.

Potential applications in levitated optomechanics experiments.

Abstract

The superposition of frequency-shifted Laguerre-Gauss modes can produce a rotating saddle-like intensity profile. When spinning fast enough, the optical forces produced by this structured light saddle generate a dynamically stable equilibrium point capable of trapping nanoparticles in a high vacuum, akin to a Paul trap but with its unique characteristics. We analyze the stability conditions and center-of-mass motion, dynamics and cooling of a nanoparticle levitated in the optical saddle trap. We expect the optical saddle to find applications in levitated optomechanics experiments requiring fast parametric modulation and inverted squeezing potential landscapes.