Characterizing and tracking single colloidal particles with video holographic microscopy

TL;DR

This paper demonstrates a method using digital holographic microscopy and Mie scattering theory to precisely characterize and track individual colloidal particles in three dimensions, measuring size, refractive index, and position with high accuracy.

Contribution

The study introduces a technique that combines digital holography and Mie theory to simultaneously determine size, refractive index, and 3D position of colloidal particles with high precision.

Findings

Measured particle radius and refractive index within 1% accuracy

Achieved nanometer in-plane and 10 nm axial resolution in tracking

Enabled real-time characterization of colloidal particles

Abstract

We use digital holographic microscopy and Mie scattering theory to simultaneously characterize and track individual colloidal particles. Each holographic snapshot provides enough information to measure a colloidal sphere's radius and refractive index to within 1%, and simultaneously to measure its three-dimensional position with nanometer in-plane precision and 10 nanometer axial resolution.