Modeling the optical properties of twisted bilayer photonic crystals  

作　　者：Haoning Tang Fan Du Stephen Carr Clayton DeVault Olivia Mello Eric Mazur 

机构地区：[1]School of Engineering and Applied Sciences,Harvard University,Cambridge,MA,02138,USA [2]Brown Theoretical Physics Center and Department of Physics,Brown University,Providence,RI,02912,USA

出　　处：《Light(Science & Applications)》2021年第9期1672-1679,共8页光（科学与应用)（英文版）

摘　　要：We demonstrate a photonic analog of twisted bilayer graphene that has ultra-flat photonic bands and exhibits extreme slow-light behavior.Our twisted bilayer photonic device,which has an operating wavelength in the C-band of the telecom window,uses two crystalline silicon photonic crystal slabs separated by a methyl methacrylate tunneling layer.We numerically determine the magic angle using a finite-element method and the corresponding photonic band structure,which exhibits a flat band over the entire Brillouin zone.This flat band causes the group velocity to approach zero and introduces light localization,which enhances the electromagnetic field at the expense of bandwidth.Using our original plane-wave continuum model,we find that the photonic system has a larger band asymmetry.The band structure can easily be engineered by adjusting the device geometry,giving significant freedom in the design of devices.Our work provides a fundamental understanding of the photonic properties of twisted bilayer photonic crystals and opens the door to the nanoscale-based enhancement of nonlinear effects.

关 键 词：TWISTED PROPERTIES TUNNELING 

分 类 号：O43[机械工程—光学工程]