Dual-beam intracavity optical trap with all-optical independent axial and radial self-feedback schemes

TL;DR

This paper introduces a dual-beam intracavity optical trap with independent control of radial and axial confinement, achieving the highest axial confinement efficiency to date, enabling advanced biological and physical studies.

Contribution

The study presents a novel dual-beam intracavity optical trapping scheme with independent feedback control, improving axial confinement efficiency significantly over previous single-beam systems.

Findings

Achieved axial confinement efficiency of 1.6×10^(-4) mW^(-1).

Demonstrated independent radial and axial self-feedback control.

Enabled trapping at very low numerical aperture (NA=0.25).

Abstract

Recently single-beam intracavity optical tweezers have been reported and achieved orders-of-magnitude higher confinement than standard optical tweezers. However, there is only one feedback loop between the trapped particle's three-dimensional position and the scattering loss of the intracavity laser. That leads to the coupling effect between the particle's radial and axial motion, and aggravates the axial confinement efficiency. Here, we present and demonstrate the dual-beam intracavity optical trap enabling independent radial and axial self-feedback control of the trapped particle, through offsetting the foci of the clockwise and counter-clockwise beams. We have achieved the axial confinement efficiency of 1.6*10^(-4) mW^(-1) experimentally at very low numerical aperture (NA=0.25), which is the highest axial confinement efficiency of the optical trap to date, to the best of our knowledge. The dual-beam intracavity optical trap will significantly expand the range of applications in the further studies of biology and physics, especially for a sample that is extremely sensitive to heat.