Optical trapping and control of nanoparticles inside evacuated hollow core photonic crystal fibers

TL;DR

This paper demonstrates an optical conveyor belt for levitated nanoparticles inside hollow-core photonic crystal fibers, enabling precise control, cooling, and pressure measurement over several centimeters, with potential for nanoparticle delivery.

Contribution

It introduces a novel method for trapping, controlling, and characterizing nanoparticles inside evacuated hollow-core fibers using optical techniques.

Findings

Successful optical trapping and conveyor belt operation over centimeters.

Linear pressure dependence observed from 0.2 mbar to 100 mbar.

Particle dynamics serve as a local probe for fiber optical and pressure profiles.

Abstract

We demonstrate an optical conveyor belt for levitated nano-particles over several centimeters inside both air-filled and evacuated hollow-core photonic crystal fibers (HCPCF). Detection of the transmitted light field allows three-dimensional read-out of the particle center-of-mass motion. An additional laser enables axial radiation pressure based feedback cooling over the full fiber length. We show that the particle dynamics is a sensitive local probe for characterizing the optical intensity profile inside the fiber as well as the pressure distribution along the fiber axis. In contrast to previous indirect measurement methods we find a linear pressure dependence inside the HCPCF extending over three orders of magnitude from 0.2 mbar to 100 mbar. A targeted application is the controlled delivery of nano-particles from ambient pressure into medium vacuum.