Optical trapping and manipulation of fluorescent polymer-based nanostructures: measuring optical properties of materials in the nanoscale range

TL;DR

This paper introduces a method using optical tweezers to measure and modulate the optical properties of fluorescent polymer nanostructures at the nanoscale, enabling precise characterization and potential sensor applications.

Contribution

It presents a novel approach to determine nanoscale optical properties of polymer nanostructures by analyzing trap stiffness, with the ability to tune properties via excitation wavelength.

Findings

Refractive index and optical anisotropy can be accurately measured.

Optical properties of nanostructures can be modulated by changing excitation wavelength.

Potential applications in sensors and optoelectronic devices.

Abstract

We present a novel approach to determine the optical properties of materials in the nanoscale range using optical tweezers (OT). Fluorescent polymer-based nanostructures (pdots) are optically trapped in a Gaussian beam OT and the trap stiffness is studied as a function of various parameters of interest. We explicitly show that properties such as the refractive index and the optical anisotropy of these nanostructures can be determined with high accuracy by comparing the experimental data to an optical force model. In particular, we demonstrate that the effective optical properties of these pdots can be modulated by changing the light wavelength that excites the sample, opening the door for a fine tuning of their optical response, with possible applications in the development of new sensors and/or other optoelectronic devices.