Haoning Tang (Harvard)
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We demonstrate the fabrication of dielectric twisted bilayer photonic crystal slabs and the direct visualization of their dispersion throughout the telecom band. We use the twist angle between the two photonic crystal slabs to tune the band structure in the optical frequency range. The measured optical response directly maps the moiré eigenmodes and is in good quantitative agreement with numerical and analytical results. All three reveal the twist-angle tunability in band structure through moiré wavevector scattering, band-folding, band-hybridization, and twist-angle tunability. This work opens the door to a variety of research opportunities in the field of bilayer nanophotonics.