Raman Spectroscopy of Single Nanoparticles in a Double-Nanohole Optical Tweezer System

TL;DR

This paper demonstrates a novel double nanohole optical tweezer system that traps single nanoparticles and records their Raman spectra, enabling material identification and analysis of multiple particles simultaneously.

Contribution

The study introduces a method combining nanoparticle trapping with Raman spectroscopy using a double nanohole system, allowing for real-time material identification of individual nanoparticles.

Findings

Successful trapping and Raman spectral recording of 20 nm nanoparticles.

Identification of characteristic Raman lines for titania and polystyrene.

Enhanced Raman signals observed with multiple nanoparticles trapped.

Abstract

A double nanohole in a metal film was used to trap nanoparticles (20 nm diameter) and simultaneously record their Raman spectrum using the trapping laser as the excitation source. This allowed for the identification of characteristic Stokes lines for titania and polystyrene nanoparticles, showing the capability for material identification of nanoparticles once trapped. Increased Raman signal is observed for the trapping of multiple nanoparticles. This system combines the benefits of nanoparticle isolation and manipulation with unique identification.