Super-resolved Second Harmonic Generation Imaging by Coherent Image Scanning Microscopy

TL;DR

This paper demonstrates super-resolved second harmonic generation microscopy using coherent image scanning microscopy with an interferometric approach to extract phase-sensitive field information, surpassing traditional intensity-based methods.

Contribution

It provides the first experimental demonstration of coherent ISM for SHG by extracting complex field amplitudes, enabling super-resolution imaging.

Findings

Successful implementation of phase-sensitive SHG microscopy

Enhanced resolution beyond diffraction limit

Potential extension to other nonlinear microscopy techniques

Abstract

We extend image scanning microscopy to second harmonic generation (SHG) by extracting the complex field amplitude of the second-harmonic beam. While the theory behind coherent image scanning microscopy (ISM) is known, an experimental demonstration wasn't yet established. The main reason is that the naive intensity-reassignment procedure cannot be used for coherent scattering as the point spread function is now defined for the field amplitude rather than for the intensity. We use an inline interferometer to demonstrate super-resolved phase-sensitive SHG microscopy by applying the ISM reassignment machinery on the resolved field. This scheme can be easily extended to third harmonic generation and stimulated Raman microscopy schemes.