Title:  Dynamic Nanophotonic Structures Leveraging Chalcogenide Phase-change Materials

Committee:

Dr. Ali Adibi, ECE, Chair, Advisor

Dr. Benjamin Klein, ECE

Dr. Wenshan Cai, ECE

Dr. Stephen Ralph, ECE

Dr. Eric Vogel, MSE

Abstract: The objective of this research is the demonstration of adaptive photonic structures leveraging phase-change chalcogenides for active manipulation of optical wavefronts in the subwavelength regime. Accordingly, pure plasmonic, all-dielectric, and hybrid plasmonic-dielectric metasurfaces are realized to spectrally, spatially, and/or temporally control the main properties of light with a high dynamic range. First, I explored and characterized the material properties of a well-established phase-change chalcogenide (i.e., germanium antimony telluride (GST)) serving as a functional material in the mainstream of dynamic phase-change nanophotonics. By investigating the underlying nature of fundamental plasmonic/photonic modes supported by rationally engineered metasurfaces, I propose hybrid configurations enabling active tuning of the amplitude, phase, and polarization of light in a small form factor framework. I have also investigated the realization of opaque and transparent micro/nanoheaters for active tuning of emerging visible phase-change metasurfaces at the pixel level. The existing challenges have been fairly resolved in this work, and potential solutions will be proposed by introducing new architectures or advancing the available state-of-the-art methods.