Signal and Noise Analysis for Chiral Structured Illumination Microscopy

TL;DR

This paper analyzes the impact of noise on chiral structured illumination microscopy, providing a theoretical framework for signal-to-noise ratio and proposing strategies to improve image quality for weak chiral signals.

Contribution

It offers an analytical description of noise effects in chiral SIM and suggests methods to enhance SNR for weak circular dichroism samples.

Findings

Signal-to-noise ratio can be analytically described in Fourier domain.

Numerical simulations verify the theoretical SNR calculations.

Strategies to improve SNR in weak chiral signals are discussed.

Abstract

Recently, chiral structured illumination microscopy has been proposed to image fluorescent chiral domains at sub-wavelength resolution. Chiral structured illumination microscopy is based on the combination of structured illumination microscopy, fluorescence-detected circular dichroism, and optical chirality engineering. Since circular dichroism of natural chiral molecules is typically weak, the differential fluorescence is also weak and can be easily buried by the noise, hampering the fidelity of the reconstructed images. In this work, we systematically study the impact of the noise on the quality and resolution of chiral domain images obtained by chiral SIM. We analytically describe the signal-to-noise ratio of the reconstructed chiral SIM image in the Fourier domain and verify our theoretical calculations with numerical demonstrations. Accordingly, we discuss the feasibility of chiral SIM in different experimental scenarios and propose possible strategies to enhance the signal-to-noise ratio for samples with weak circular dichroism.