A customizable digital holographic microscope

Published: 2 May 2024| Version 2 | DOI: 10.17632/k38sfd28py.2
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Description

We propose a low-cost, compact, and portable holographic microscope designed for the characterization of micrometric particles suspended in a liquid. This system is built around a commercial optical microscope by substituting its illumination source (a light-emitting diode) with a collimated laser beam. Similarly, a quartz flow cell replaces the microscope glass slide using 3D-printed custom mounting. With the hardware presented in this paper, the holographic imaging of the electromagnetic fields emitted by the objects that intercept the laser beam achieves a resolution close to that achieved with optical microscopes, but with a much larger depth of field. Once a hologram is recorded, a variety of morphological and optical features, including particle projected section, aspect ratio, and extinction cross-section can be extracted. Additionally, we introduce a remote system control that enables users to process the acquired holograms to a remote computational device. This work encompasses a comprehensive description of the methodology of the image processing in holographic microscopy, and a series of validation measurements conducted using calibrated particles. This technique is suitable for the characterization of airborne particles found in snow, firn and ice; here we report experimental results obtained from Alpine ice cores. We include the 3d printer design files, the Holography tutorial in jupyter, and the files to control remotely the camera, the Pycamera project in python

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Institutions

University of Milano-Bicocca

Departments

Department of Earth and Environmental Sciences

Categories

Glaciology, Holography

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