High-resolution mapping of the optical near-field components at a triangular nano-aperture

Area of Science:

• Nanophotonics
• Optical Microscopy
• Molecular Imaging

Background:

• Scanning near-field optical microscopy (SNOM) offers sub-wavelength resolution.
• Characterizing vectorial electric fields at the nanoscale is crucial for understanding light-matter interactions.

Purpose of the Study:

• To develop a nanoscale probe for high-resolution imaging.
• To map the vectorial electric field distribution of a triangular nano-aperture.
• To determine the orientation of fluorescent molecules used as detectors.

Main Methods:

• Utilized a triangular nano-aperture in an aluminum film as a SNOM probe.
• Employed single fluorescent molecules as point detectors to sense electric field components.
• Performed numerical simulations to validate experimental findings.

Main Results:

• Achieved optical resolution down to 30 nm for imaging single fluorescent molecules.
• Successfully mapped the vectorial components of the electric field distribution at the aperture.
• Determined the precise orientations of the probing molecules.

Conclusions:

• The triangular nano-aperture probe enables high-resolution nanoscale imaging.
• The combined experimental and simulation approach accurately characterizes near-field optical properties.
• This technique provides insights into light polarization and molecular orientation at the nanoscale.