# Simultaneous three-wavelength unwrapping using external digital holographic multiplexing module

## TL;DR

This paper introduces an external digital holographic multiplexing system that captures three wavelengths simultaneously, enabling phase unwrapping for thicker samples without increased noise, demonstrated on micro-channel and cell imaging.

## Contribution

The paper presents a novel external interferometric setup for simultaneous three-wavelength holography, improving phase unwrapping capabilities for thicker samples without noise escalation.

## Key findings

- Successful three-wavelength phase unwrapping for thick samples
- Simultaneous acquisition of three holograms without overlap
- Enhanced phase imaging for micro-channel and cell samples

## Abstract

We present an external interferometric setup that is able to simultaneously acquire three wavelengths of the same sample instance without scanning or multiple exposures. This setup projects onto the monochrome digital camera three off-axis holograms with rotated fringe orientations, each from a different wavelength channel, without overlap in the spatial-frequency domain, and thus allows the full reconstruction of the three complex wavefronts from the three wavelength channels. We use this new setup for three-wavelength phase unwrapping, allowing phase imaging of thicker objects than possible with a single wavelength, but without the increased level of noise. We demonstrate the proposed technique for micro-channel profiling and label-free cell imaging.

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Source: https://tomesphere.com/paper/1903.12056