Fig. 3: A variety of etched hexagonal hole arrays and their optical properties.
From: Transition metal dichalcogenide metamaterials with atomic precision
a SEM images of hexagonal hole arrays with various rotational angles (15° step) with respect to the orientation of individual hexagonal holes in a WS2 flake. The orange-dashed and blue hexagons identify the orientations of hexagonal lattice arrays and individual hexagonal holes, respectively. b SEM images of honeycomb and bow-tie hexagonal hole arrays with fixed lattice periodicity but different hole sizes (bigger holes are shown to the right). c True-color optical microscope image and reflectivity spectra of hexagonal arrays with various hole sizes and lattice orientations in ~70 nm thick WS2. The bottom row of the optical image consists of honeycomb arrays with variable hole sizes ranging from 240 to 300 nm (left to right) and a fixed lattice pitch of 400 nm, and their SEM images are shown, respectively. The scale bar is 500 nm. c Experimental and d simulated reflectivity spectra. Dashed lines are guides for an eye, indicating the A-exciton energy and the avoided crossing.
