Simultaneous Imaging Achiral and Chiral Domains beyond Diffraction Limit by Structured-illumination Microscopy

TL;DR

This paper introduces a double structured-illumination microscopy technique that enables simultaneous super-resolution imaging of both achiral and chiral fluorescent domains, overcoming previous limitations of chirality discrimination.

Contribution

The paper presents an advanced double SIM method that structures both intensity and optical chirality of illumination to achieve simultaneous sub-wavelength imaging of achiral and chiral domains.

Findings

Theoretical feasibility demonstrated with synthetic samples.

Allows concurrent super-resolution imaging of achiral and chiral domains.

Uses interfering circularly polarized light for structured illumination.

Abstract

Modern optical microscopy methods have been advanced to provide super resolution at high imaging speed, but not chirality discriminative. We recently proposed chiral structured-illumination microscopy (SIM) method to image chiral fluorescent domains at sub-wavelength resolution. Chiral SIM is suitable for imaging chiral domains at sub-wavelength resolution but loses the high spatial frequency of the achiral ones. In order to obtain the full picture of all fluorescent domains at sub-wavelength resolution, we propose an advanced version of chiral SIM, termed double SIM, which enables simultaneous imaging of achiral and chiral domains at sub-wavelength resolution. In double SIM, the illumination field must be spatially structured both in the intensity and optical chirality so that moir\'e effects can be concurrently generated on the achiral and chiral fluorescent domains of a sample. This allows down-modulating the high spatial frequency of both domains at the same time and thus provides sub-wavelength details after image reconstruction. To generate the illumination field with concurrently structured intensity and optical chirality, we propose interfering two coherent circularly polarized light with the same handedness at the sample plane. We introduce the working principle of double SIM and theoretically demonstrate the feasibility of this method using different kinds of synthetic samples.