Flow visualization and flow cytometry with holographic video microscopy

Abstract

The video stream captured by an in-line holographic microscope can be analyzed on a frame-by-frame basis to track individual colloidal particles' three-dimensional motions with nanometer resolution, and simultaneously to measure their sizes and refractive indexes. An efficient particle-tracking algorithm automates initial position estimation with sufficient accuracy to enable unattended holographic particle tracking and characterization. In this work, we demonstrated this approach to flow visualization in a microfluidic channel and also to flow cytometry of micrometer-scale colloidal spheres.