Fabrication of Twisted Bilayer Photonic Crystals

Student’s name: Alsyl Enriquez Home Institution: University of California, San Diego NNCI Site: CNS @ Harvard University REU Principal Investigator: Eric Mazur – Department of Physics, Harvard University REU Mentor: Fan Du - Department of Physics, Harvard University Abstract: In this study, we investigate the fabrication and optimization of a twisted bilayer photonic crystal (TBPhC). Utilizing a detailed fabrication process, we create TBPhC structures by twisting two photonic crystal slabs relative to each other at precise angles. The resulting moiré patterns significantly alter the photonic band structure, enabling tunable optical properties. Characterization techniques, including momentum space–resolved optical response measurements and band structure analysis, are employed to assess the impact of various twist angles on the photonic behavior. Our findings reveal a high degree of tunability in the optical band structure due to interlayer coupling and moiré scattering. This research not only provides insights into the complex optical phenomena in TBPhC systems but also offers a pathway for developing advanced photonic devices with customizable optical properties. Future work will focus on optimizing the fabrication process to enhance the reproducibility and performance of these structures, aiming to integrate them into practical applications such as tunable filters, sensors, and optical communication systems.