From Event: SPIE Defense + Commercial Sensing, 2023
Polarimetry imaging technology has progressed rapidly in recent years. It promises advances in various fields of application, including remote sensing, medical imaging, molecular sensing, and many areas of defense and homeland security application. Conventional polarimetry is not flexible and has remained difficult to implement due to the complexity of optics and moving parts, and generally, it is bulky and costly. Recent advances in the design, micro/nanofabrication, and testing of metasurfaces have opened tremendous opportunities by simplifying the optics pathway. These sub-wavelength and flat structures can be engineered to transform the propagation, phase, and polarization of light. It is now conceivable to replace the carefully aligned optical components with a single well-designed metasurface. In this work, we present the design, fabrication, and integration of a multiplexed dielectric metasurface operating at 532 nm, which is of great interest for underwater imaging. The metasurface developed in this work spatially diffracts polarizations, resulting in demultiplexing the polarization, and the intensity of each polarization was recorded to determine the Stokes parameters. We will discuss the optimization process of designing the dielectric metasurface to recover the Stokes parameters for imaging and the degree of polarization. With the FDTD simulation, we explored the metasurface design parameter space to achieve better transmission and phase control. The incorporation of Pancharatnam–Berry phase and cross-talk among the orthogonal components of linearly and circularly polarized light were evaluated. The designed metasurface was fabricated using electron beam lithography and ICP-RIE etching. Finally, the fabricated metasurface was integrated with a time-of-flight multi-pixel imager.
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Anirban Swakshar, Karsten Schnier, Carson Moseley, Cooper Coldwell, Jonathan Martini, Oladipupo Adeoluwa, Sevgi Gurbuz, Seongsin Margaret Kim, and Patrick Kung, "Polarization de-multiplexing metasurface-based polarimetric imaging with time of flight multi-pixel imager," Proc. SPIE 12514, Image Sensing Technologies: Materials, Devices, Systems, and Applications X, 1251407 (Presented at SPIE Defense + Commercial Sensing: May 02, 2023; Published: 15 June 2023); https://doi.org/10.1117/12.2664137.