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42 UEC Int’l Mini-Conference No.52

Underwater 3D Imaging by a Functionally Integrated Waveguide

Illuminator-based Digital Holographic Microscope

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Maryam FAHEEM ,Kenta HAYASHI ,Katsunari OKAMOTO ,Ayaka TABUCHI , Eriko WATANABE 1
1.Department of Engineering Sciences
The University of Electro-Communications
Tokyo, Japan
2. Okamoto Laboratory

Keywords: Digital Holography, Microscopy, Underwater Imaging, Optical Waveguide, Common Path
Digital Holography, Functionally Integrated Waveguide Illuminator.

Abstract

In the quest to address the issues of complexity presented by the traditional digital holographic mi-
croscopes (DHMs), we designed and fabricated a novel optical waveguide device called the Functionally
Integrated Waveguide Illuminator (FIWI). FIWI, a single-chip waveguide device in size of 25 ʷ 15 mm,
generates two adjacent point light sources and induces interference with desired phase shifts. It satisfies
the condition of common path digital holography and allows elimination of the need for any additional
optical element such as the beam splitter. Thus, the development of this device makes the optical
setup for DHM compact simple, Lensless, and easy to align. In the current study, the functionality
of the device is experimentally tested in air and scattering media (water). We succeeded in capturing
the sample object ʟs reconstructed images in both types of media using the four-phase shift method
and light backpropagation calculations. We demonstrate that the spatial resolution of FIWI-DHM is
1.6 µm from the Modulation Transfer Function analysis. Additionally, we succeeded in a real-time
monochromatic movie reconstruction of the underwater microorganisms in 3D space. This waveguide
device has the potential to offer a wide range of applications in advanced optical imaging systems for
3D Imaging of microscopic entities in random media.

∗ The author is supported by (AiQuSci) MEXT Scholar-
ship.