Mapping standing-wave cavity modes with a commercial scanning near-field microscope tip

TL;DR

This paper presents a method using a commercial SNOM tip to map standing-wave patterns inside a Fabry-Perot cavity with sub-wavelength resolution, enabling precise mode characterization and positioning.

Contribution

The paper introduces a novel approach to map cavity modes with a SNOM tip and demonstrates its application to fiber microcavities for detailed mode analysis.

Findings

Successful mapping of standing-wave patterns with sub-wavelength resolution.

Determination of relative antinode positions at different wavelengths.

Precise positioning of microscope objectives using the SNOM tip as a point source.

Abstract

We describe a method to map the standing-wave pattern inside a Fabry-Perot optical cavity with sub-wavelength resolution by perturbing it with a commercially available scanning near-field optical microscope (SNOM) tip. The method is applied to a fiber Fabry-Perot microcavity. We demonstrate its use to determine the relative position of the antinodes at two different wavelengths. In addition, we use the SNOM tip as a point-like source allowing precise positioning of a microscope objective with respect to the cavity mode.