Two-color differential dynamic microscopy for capturing fast dynamics

TL;DR

This paper introduces a two-color differential dynamic microscopy technique that uses sequential spectral illumination and color imaging to measure microscopic dynamics faster than the camera frame rate, expanding DDM capabilities.

Contribution

The paper presents a novel two-color DDM method that enables capturing fast microscopic dynamics beyond traditional camera frame rate limitations.

Findings

Successfully measures dynamics faster than camera frame rate.

Uses spectral separation and pulsed illumination for enhanced temporal resolution.

Extends DDM applicability to rapid processes in soft matter and biophysics.

Abstract

Differential dynamic microscopy (DDM) is increasingly used in the fields of soft matter physics and biophysics to extract the dynamics of microscopic objects across a range of wavevectors using optical microscopy. Standard DDM is limited to detecting dynamics no faster than the camera frame rate. We report on an extension to DDM where we sequentially illuminate the sample with spectrally-distinct light and image with a color camera. By pulsing blue and then red light separated by a lag time much smaller than the camera's exposure time we are able to use this two-color DDM method to measure dynamics occurring much faster than the camera frame rate.