With the continuous advancement of imaging technologies, imaging devices are no longer limited to the exclusive measurement of optical intensity (at the expense of all other degrees of freedom of the incident light) in a standard single-aperture configuration. Increasingly demanding applications are currently driving the exploration of more complex imaging capabilities, such as phase contrast imaging, wave front sensing, optical spatial filtering, and compound-eye vision. Many of these applications also require highly integrated, lightweight, and compact designs without sacrificing performance. Thanks to recent developments in micro- and nanophotonics, planar devices such as metasurfaces have emerged as a powerful new paradigm to construct optical elements with extreme miniaturization and high design flexibility. Sophisticated simulation tools and high-resolution fabrication techniques have also become available to enable the implementation of these compact subwavelength structures in academic and industrial labs. In this dissertation, I will present my work aimed at achieving directional light sensing by directly integrating composite plasmonic metasurfaces on the illumination windows of standard planar photodetectors. The devices developed in this work feature sharp detection peaks in their angular response with three different types of behaviors: symmetric around the device surface normal, asymmetric with nearly linear angular variations around normal incidence, and geometrically tunable single peaks up to over 60 degrees. The performance of the proposed metasurfaces has been optimized by full-wave numerical simulations, and experimental devices have been fabricated and tested with a custom-designed measurement setup. The measured angular characteristics were then used to computationally demonstrate incoherent edge enhancement for computer vision and quantitative phase-contrast imaging for biomedical microscopy. Importantly, the device fabrication process has also been upgraded to wafer scale, further promoting the possibility of batch-production of our devices.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/48870 |
| Date | 24 May 2024 |
| Creators | Liu, Jianing |
| Contributors | Paiella, Roberto |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
| Rights | Attribution-NonCommercial 4.0 International, http://creativecommons.org/licenses/by-nc/4.0/ |
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