BIJECTIVE ILLUMINATION COLLECTION IMAGING: HIGHRE-SOLUTION TOMOGRAPHY IN THREE DIMENSIONS
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Authors
Pahlevaninezhad, Masoud
Date
Type
thesis
Language
eng
Keyword
Metasurface , High-resolution , Imaging , Depth of focus , OCT
Alternative Title
Abstract
High-resolution optical imaging in three imensions from sub-surface of the issues enables numerous biological studies and clinical applications. High-resolution images are conventionally achieved by tight focusing of light into one point. Dictated by diffraction, tightly focused light spreads rapidly away from the focal point, hampering acquisition of high-resolution information in a relatively large depth range. As a result, microscopic imaging systems are often capable of capturing images with no depth information.
This thesis presents a solution to vercome this fundamental limitation in optical imaging through a particular architecture of illumination and collection light paths, liberating optical imaging from the restrictions imposed by diffraction. This technique, termed bijective illumination collection imaging (BICI), decouples lateral resolution from depth of focus by establishing a one-to-one correspondence (bijection) along a focal line between the illumination and collection light paths.
Unlike the traditional approach of imaging from a single focal point, BICI allows simultaneous acquisition of high-resolution images from a focal line along which lateral resolution is maintained. This approach addresses the fundamental question of how light intensity should be distributed to obtain high-resolution imaging in three-dimensions within a large depth range.
BICI uses the latest nano-optic technology, namely, metasurfaces, to shape the illumination and collection light paths. Implemented in optical coherence tomography (OCT), BICI’s impact on resolution of imaging is assessed. We demonstrate tissue imaging at 1.3 μm wavelength with approximately 3.2 μm lateral resolution maintained nearly intact over 1.25 mm depth of focus, 12- fold larger imaging depth of focus compared to that obtained using an ideal Gaussian beam with the same lateral resolution. A one-to-one comparison of tissue images obtained from BICI and the conventional OCT approach proves the former’s ability to accomplish high-resolution images within a large depth range.
The presented approach, BICI, entails no additional acquisition or computational burden and can be implemented across various wavelength ranges as its working principle remains unaltered with a wavelength change. Using metasurfaces, BICI can be feasibly miniaturized into endoscopic devices for high-resolution imaging in clinical settings. Demonstrated through OCT imaging, this approach serves as a foundation for high-resolution volumetric imaging which might be also adapted across the other existing optical modalities to capture high-resolution depth-resolved images.
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Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
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ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.