Feasibility of using LSPR on the biased nanotip to realize the atomic-resolution near-field optical detection

TL;DR

This paper develops a theoretical model for near-field optical detection using LSPR on biased nanotips, demonstrating that electron density tuning via bias voltage can control LSPR properties for atomic-resolution detection.

Contribution

It introduces a new theoretical model linking electron density and LSPR in biased nanotips, verified by spectral tests on various metal nanospheres.

Findings

LSPR frequency depends solely on localized electron density.

Bias voltage can tune the LSPR frequency and intensity.

Spectral tests confirm the theoretical model.

Abstract

A near-field optical detection method and its theoretical model are developed, which follow from an algebra-based conclusion: in the localized surface plasmon resonance (LSPR) region, the extinction coefficient of a metal nanosphere is the sesquiplicate proportion of the localized electron density. Eleven spectral tests of gold, silver, and aluminum nanospheres are used to verify this model. For a metal nanosphere, the frequency and intensity of the LSPR are dependent on the localized electron density only. The electron density can be tuned by adjusting the bias voltage, so the bias can enhance or inhibit the LSPR frequency of the metal nanosphere.