High-resolution Collinear Chiral Sum Frequency Generation Microscopy by Using Vectorial Beam

TL;DR

This paper introduces a collinear chiral sum frequency generation microscopy technique using vectorial beams, achieving higher spatial resolution and enabling diffraction-limited, label-free imaging of chirality.

Contribution

The work presents a novel collinear C-SFG microscopy method utilizing longitudinal z-polarized vectorial fields, improving spatial resolution over traditional non-collinear schemes.

Findings

Achieved ~1.4 times resolution enhancement in lateral and longitudinal directions.

Demonstrated diffraction-limited, label-free chiral imaging.

Provided a new approach for high-resolution SFG microscopy.

Abstract

In chiral sum frequency generation (C-SFG), the chiral nature of ${\chi}^{(2)}$ requires the three involved electric fields to be pairwise non-parallel, leading to the traditional non-collinear configuration which is a hindrance for achieving diffraction limited resolution while utilizing it as a label-free imaging contrast mechanism . Here we propose a collinear C-SFG (CC-SFG) microscopy modality by using longitudinal z-polarized vectorial field. Label-free chiral imaging with enhanced spatial resolution (~1.4 times improvement in one lateral and the longitudinal directions over the traditional non-collinear scheme) is demonstrated, providing a new path for SFG microscopy with diffraction-limited resolution for mapping chirality.