Optical trapping based on microring resonators with transverse slot structure

TL;DR

This paper introduces a novel transverse slot microring resonator that significantly enhances optical trapping forces on nanoparticles, outperforming traditional waveguides and resonators, and advancing micro/nanomanipulation techniques.

Contribution

The study demonstrates that integrating a transverse slot into microring resonators greatly increases optical trapping forces on nanoparticles, offering a new design for improved manipulation.

Findings

Maximum optical force reached 3988.8 pN/W for 50 nm particles

Force is 2292 times higher than in straight waveguides

Force is 2.266 times higher than in standard microring resonators

Abstract

Over the past few decades, optical manipulation has emerged as a highly successful tool in various fields, such as biology, micro/nanorobotics, and physics. Among the different techniques, the transverse slot optical waveguide has shown remarkable potential in enhancing the field and significantly improving optical trapping capabilities. Additionally, microring resonators have demonstrated the ability to enhance the field at specific resonance wavelengths, enabling the manipulation and capture of particles. In this study, we investigated the impact of the structure on nanoparticle capture by introducing a 50 nm transverse slot in a 5 {\mu}m microring resonator. Through the integration of a transverse slot in the microring resonator, we observed a substantial increase in the maximum bound optical power for a nanosphere with a refractive index of 1.6 and a diameter of 50 nm, reaching 3988.8 pN/W. This value is 2292 times higher than the maximum optical force in a straight waveguide and 2.266 times higher than the maximum optical force in a microring resonator. The proposed structure significantly enhances the optical trapping capabilities for nanoscale particles, thus paving the way for the development of advanced micro/nanomanipulation techniques.