Continuous wave multi-pass imaging flow cytometry

TL;DR

This paper introduces a multi-pass imaging flow cytometry technique that enhances contrast and sensitivity for high-speed, label-free imaging of blood cells, approaching quantum measurement limits and surpassing current quantum light sources.

Contribution

It presents a novel multi-pass imaging method that significantly improves contrast and sensitivity in flow cytometry, nearing quantum-limited measurement performance.

Findings

Achieves up to four passes for enhanced contrast and signal-to-noise ratio.

Approaches the quantum limit of measurement sensitivity.

Extends optimal imaging to weakly absorbing samples.

Abstract

We present a wide-field multi-pass implementation of label-free imaging flow cytometry. Our technique is shown for high-speed flow imaging of ensembles of human red blood cells with up to four passes, demonstrating x4 enhancement in contrast and signal-to-noise. We show that our technique approaches close to the quantum limit of measurement sensitivity, extending the range of optimal imaging to samples in the weakly absorbing regime. This allows for near optimal imaging sensitivity and throughput in a practical scenario of imaging a dynamic sample under limited illumination intensity, surpassing the sensitivity achieved with currently available quantum light sources.