Topology Optimization for Volumetric Meta-Optics

The properties of many optical components are determined simply by their shape: lens, gratings, prisms, etc. Engineered optical materials also control electromagnetic propagation by virtue of their shape, but with intriguing properties that arise from shaping the element at the sub-wavelength scale. These shapes often include a lattice of sub-wavelength ellipses, rectangles, or other shapes that are simple to describe with a handful of parameters. The purpose of topology optimization is to set aside these parameterizable shapes, and instead directly optimize the permittivity distribution with sub-wavelength precision. This gives rise to non-intuitively shaped optical elements that are uniquely suited to the task they are prescribed. This talk will describe how to efficiently design these elements using state-of-the-art inverse-design procedures, with a particular focus on reducing computational complexity and constraining solutions to only shapes that can be fabricated. We will also focus on the relative advantages of 2-dimensional engineered surfaces versus 3-dimension engineered materials (termed “EnMats”, or “volumetric metaoptics”), and conclude by showcasing some of many applications these optical elements and design procedures are suitable for.