Position:  Postdoctoral Researcher

Current Institution:  University of Pennsylvania

Abstract:  From Solving Equations to Compact Optical Devices: The Fascinating World of Nanoscale Light-Matter Interactions

Metamaterials hold the potential to bring innovative ideas into the emerging fields of nano-optics and nano-photonics. The physical properties of these artificially engineered structures can be designed through their subwavelength constitutive meta-molecules, providing an interesting platform to develop the next generation of optical devices with enhanced capabilities and smaller footprints. Within this context here, we present a fully-integrable metamaterial platform to solve complicated mathematical equations in the form of linear integral equations, using electromagnetic waves. An equation is intrinsically different from a forward problem (such as taking derivative of a signal) and entails a feedback mechanism. To address this point, our design employs a network of parallel waveguides as an external or internal feedback path for the optical wave, which along with the specially designed metamaterial operator, closes the signal loop and generates the solution to the integral equation in the steady states (in collaboration with Dr. Edwards and Professor Engheta at UPenn). This proposal enables the implementation of conceptually any linear integral equation, even with a translationally variant kernel. In the long term, this work is expected to provide the foundation for high-speed, ultra-small, and low-power analog optical processors. In the same context, yet for different applications, we also propose a new technique to achieve free-space optical modulation and interferometry with compact dielectric metasurfaces. Metasurfaces are two-dimensional counterparts of metamaterials that can be designed to mimic the functionality of conventional optical elements over orders of magnitude smaller footprints. In this project we introduce metasurface doublets for applications in modulators, waveplates, and pulse compression, suitable for mass-produced, compact, and cheap optical devices.

Bio:
Nasim Mohammadi Estakhri is currently a postdoctoral researcher in Professor Nader Engheta’s group at UPenn.  She received a PhD in electrical engineering from the University of Texas at Austin in 2016 with her thesis on “Manipulating Light-Matter Interactions with Plasmonic Metamolecules and Metasurfaces”.  She received a master’s degree (summa cum laude highest rank in engineering program) in 2011 and a bachelor’s degree in 2007 in electrical engineering fields and waves, both from the University of Tehran in Iran.  Her work has appeared in several prestigious journals.  She received the George J. Heuer Jr. PhD Endowed Graduate Fellowship from UT at Austin, honorable mention at IEEE AP-S International Symposium student paper competition, Professional Development award from UT at Austin, and the IEEE Photonics Society Graduate Student Fellowship in 2016.  She received the 2018 DMP Post-Doctoral Travel Award by APS and was invited to Stanford’s EECS Rising Stars workshop in 2017.