08/04/2025
By Danielle Fretwell

The Francis College of Engineering, Department of Electrical and Computer Engineering, invites you to attend a Doctoral Dissertation Proposal defense by Yi Huang on: "Inverse-Designed Reconfigurable Metasurfaces for Wave-Based Analog Computing."

Candidate Name: Yi Huang
Degree: Doctoral
Defense Date: Monday, Aug. 18, 2025
Time: 2 - 4 p.m.
Location: Perry Hall, Room 115

Committee:

  • Advisor: Hualiang Zhang, Professor, Electrical & Computer Engineering, University of Massachusetts Lowell
  • Viktor A Podolskiy, Professor, Physics, University of Massachusetts Lowell
  • Alkim Akyurtlu, Professor, Electrical & Computer Engineering, University of Massachusetts Lowell
  • Xingwei Wang, Professor, Electrical & Computer Engineering, University of Massachusetts Lowell

Abstract:
Wave-based computing, as a branch of analog computing alternative to modern digital computing infrastructures, has received increasing attention because of its potential to overcome the limitations of chip scaling and energy consumption. By mapping mathematical representations to wave properties, including amplitudes, phases, and diffraction, wave-based computing offers the potential to perform complex mathematical operations through the physical interactions that skip the analog-to-digital conversion, thus achieving high parallelism and energy efficiency. With an unprecedented surge in computational demands driven by emerging data-intensive applications, especially in the fields of information and communication technology (ICT), wave-based computing has been regarded as a promising solution to provide complementary capabilities that fill the gap between computational resources and the demand for specialized computing tasks.

Metasurfaces, the artificially engineered structures, are promising candidates to be employed in wave-based computing systems, as they offer versatile and precise manipulation of electromagnetic (EM) waves that can be tailored to perform complicated mathematical operations, such as differentiation, integration, and matrix multiplication. However, designing high-performance metasurfaces with sophisticated functionalities remains challenging due to the need for optimization over a multi-dimensional design space and the high computational cost of the traditional rigorous coupled-wave analysis (RCWA) based techniques. Rigorous diffraction interface theory (R-DIT) is proposed as a powerful tool to improve the design efficiency of RCWA by using an eigendecomposition-free approach. On the other
hand, inverse design techniques, the emerging design methodologies that start from the desired functionalities to systematically optimize the design parameters, have been widely adopted across various engineering fields. A comprehensive inverse design framework based on R-DIT that seamlessly integrates flexible parameterization still remains underdeveloped.

This proposal aims to develop a wave-based computing system employing metasurfaces, in which a comprehensive inverse design framework based on R-DIT is introduced to complete the design of the required metasurfaces. First, the background and motivation of wave-based computing will be presented. Second, the recent progress of wave-based computing systems will be reviewed. Third, the proposed inverse design framework will be illustrated with case studies. Finally, a reconfigurable metasurface-based wave-based computing system that solves integral equations will be presented and discussed.