Plasmonic nano-optical trap stiffness measurements and design optimization

TL;DR

This paper introduces a fluorescence correlation-based method to measure and optimize the trap stiffness of plasmonic nano-optical tweezers, significantly enhancing their performance for nanomanipulation tasks.

Contribution

It presents a novel experimental approach for trap stiffness measurement and provides design optimization guidelines for double nanohole apertures to achieve higher trap stiffness.

Findings

Trap stiffness measured using fluorescence correlation.

Optimized nanohole design increases trap stiffness 10x.

Method offers a simple way to improve nano-optical tweezers.

Abstract

Plasmonic nano-optical tweezers enable the non-invasive manipulation of nano-objects under low illumination intensities, and have become a powerful tool for nanotechnology and biophysics. However, measuring the trap stiffness of nanotweezers remains a complicated task, which hinders the development of plasmonic trapping. Here, we describe an experimental method to measure the trap stiffness based on the temporal correlation of the fluorescence from the trapped object. The method is applied to characterize the trap stiffness in different double nanohole apertures and explore the influence of their design parameters in relationship with numerical simulations. Optimizing the double nanohole design achieves a trap stiffness 10x larger than the previous state-of-the-art. The experimental method and the design guidelines discussed here offer a simple and efficient way to improve the performance of nano-optical tweezers.