Accurate single-nanoparticle sizing down to 3 nm with an optofluidic microcavity
Abstract
Nanoparticles are ubiquitous, and methods that reveal insights into single-particle properties are highly desired to enable their advanced characterization. Techniques that achieve label-free single-nanoparticle detection often lack bandwidth or do not provide quantitative information. Here, we present a cavity-based dispersive sensing method that achieves a high bandwidth to capture all relevant timescales of translational diffusion, and a sensitivity to detect and size single particles with diameters down to 3 nm. We develop an analytical model describing the autocorrelation function for particle diffusion in a standing-wave sensing geometry and propose a method to address the challenges posed by the transient nature of single-particle signals. With this, we achieve quantitative particle sizing with high precision and accuracy, and provide an important tool to analyze single-particle diffusion.
Keywords
Cite
@article{arxiv.2507.05236,
title = {Accurate single-nanoparticle sizing down to 3 nm with an optofluidic microcavity},
author = {Shalom Palkhivala and Larissa Kohler and Christian Ritschel and Claus Feldmann and David Hunger},
journal= {arXiv preprint arXiv:2507.05236},
year = {2025}
}