The objective of this work is to incorporate nanoscale disorder in a class of visible and near-infrared photonic crystal devices in order to achieve device figures of merit up to two orders of magnitude better than in existing state-of-the-art devices without nanoscale disorder. The approach is based on nonlinear topology optimization, whereby a 2D photonic crystal device can be designed so that the arrangement of dielectric material and air is optimally configured to yield some desired device output. Preliminary results show that, for example, a 2D photonic crystal waveguide with tailored nanoscale features near the crystal/air interface can exhibit focusing characteristics that significantly reduce losses in coupling to an external optical fiber. The necessary fabrication resolution to achieve such a device can be accommodated by advanced nanolithographic techniques. In this work, a similar photonic crystal device designed using topology optimization will be fabricated and characterized to validate and advance the approach.
The broader technical impact of the work is to advance a novel and multidisciplinary solution to a significant limitation of real nanophotonic devices, potentially leading to a major breakthrough in photonic crystal device technology. The work also has significant broader impact in educating engineering students. As part of the work, the PI will help to develop an undergraduate course that will introduce mechanical engineering students to problems in electronic materials, and the project team will work to integrate senior design projects between the Mechanical Engineering and Electrical Engineering curricula at the University of Illinois at Urbana-Champaign.
