Remote optical sensing on the nanometer scale with a bowtie aperture nano-antenna on a SNOM fiber tip

TL;DR

This paper introduces a novel remote optical sensing method using a bowtie aperture nano-antenna on a SNOM fiber tip, enabling non-contact, high-precision nano-positioning and environmental monitoring at the nanometer scale.

Contribution

It demonstrates the first use of a bowtie-aperture nano-antenna for remote sensing beyond its plasmonic confinement, enabling non-contact, high-precision nano-positioning.

Findings

Remote sensing up to 300 nm distance from silicon surface.

Sub-nanometer accuracy in spacing control.

Potential for nano-positioning techniques based on resonance monitoring.

Abstract

Plasmonic nano-antennas have proven the outstanding ability of sensing chemical and physical processes down to the nano-meter scale. Sensing is usually achieved within the highly confined optical fields generated resonantly by the nano-antennas, i.e. in contact to the nano-structures. In these paper, We demonstrate the sensing capability of nano-antennas to their larger scale environment, well beyond their plasmonic confinement volume, leading to the concept of 'remote' (non contact) sensing on the nano-meter scale. On the basis of a bowtie-aperture nano-antenna (BNA) integrated at the apex of a SNOM fiber tip, we introduce an ultra-compact, move-able and background-free optical nano-sensor for the remote sensing of a silicon surface (up to distance of 300 nm). Sensitivity of the BNA to its large scale environment is high enough to expect the monitoring and control of the spacing between the nano-antenna and a silicon surface with sub-nano-meter accuracy. This work paves the way towards a new class of nano-positionning technique, based on nano-antenna resonance monitoring, that are alternative to nano-mechanical and optical interference-based devices.