Resonance modes in moiré photonic patterns for twistoptics

Abstract

Twistronics has been studied for manipulating electronic properties through a twist angle in the formed moiré superlattices of two dimensional layer materials. In this paper, we study twistoptics for manipulating optical properties in twisted moiré photonic patterns without physical rotations. We describe a theoretic approach for the formation of single-layer twisted photonic pattern in square and triangular lattices through an interference of two sets of laser beams arranged in two cone geometries. The moiré period and the size of unit super-cell of moiré patterns are related to the twist angle that is calculated from the wavevector ratio of laser beams. The bright and dark regions in moiré photonic pattern in triangular lattices are reversible. We simulate E-field intensities and their cavity quality factors for resonance modes in moiré photonic pattern in square lattices. Due to the bandgap dislocation between the bright and dark regions, the resonance modes with very high quality-factors appears near bandgap edges for the moiré photonic pattern with a twist angle of 9.5 degrees. At the low frequency range, the resonance modes can be explained as Mie resonances. The cavity quality factor decreases for resonance modes when the twist angle is increased to 22.6 degrees.

Experimental probe of twist angle–dependent band structure of on-chip optical bilayer photonic crystal

“…There are emerging interests in using moiré physics to engineer optical dispersion. For example, moiré-patterned single-layer (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15) and twisted-bilayer (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) photonic structures exhibit ultraflat bands with no dispersion. The moiré pattern created by twisting two photonic structures relative to each other gives rise to distinctive optical properties, including nonlinear enhancement (36) and anisotropic dispersion (37).…”

Photonic Band Gaps and Resonance Modes in 2D Twisted Moiré Photonic Crystal

“…Moiré photonic crystals have also been fabricated by holographic fabrication through laser interference of two sets of laser beams arranged in two-cone geometry with different cone angles [31][32][33][34][35][36][37][38]. Due to the gradient pattern and super-cell in the photonic crystal, this has also been named graded photonic super-crystal [37][38][39] or graded photonic superquasi-crystal [35].…”

“…Due to the gradient pattern and super-cell in the photonic crystal, this has also been named graded photonic super-crystal [37][38][39] or graded photonic superquasi-crystal [35]. In contrast to twisted bilayer 2D materials and twisted bilayer photonic crystal, two mutually twisted optical lattices generated by laser interference will interfere further and form a single layer twisted photonic crystal if we consider the 2D case [36].…”