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Published March 22, 2019 | Supplemental Material + Published
Journal Article Open

Probing the Band Structure of Topological Silicon Photonic Lattices in the Visible Spectrum


We study two-dimensional hexagonal photonic lattices of silicon Mie resonators with a topological optical band structure in the visible spectral range. We use 30 keV electrons focused to nanoscale spots to map the local optical density of states in topological photonic lattices with deeply subwavelength resolution. By slightly shrinking or expanding the unit cell, we form hexagonal superstructures and observe the opening of a band gap and a splitting of the double-degenerate Dirac cones, which correspond to topologically trivial and nontrivial phases. Optical transmission spectroscopy shows evidence of topological edge states at the domain walls between topological and trivial lattices.

Additional Information

© 2019 American Physical Society. (Received 16 July 2018; published 21 March 2019) This work was supported by U.S. Department of Energy (DOE) Office of Science Grant No. DE-FG02-07ER46405 (fabrication), the Air Force Office of Scientific Research under Grant No. FA9550-16-1-0019 (characterization) and MURI Grant No. FA9550-17-1-0002, the National Science Foundation, the research program of the Netherlands Organization for Scientific Research (NWO), and the European Research Counsel (Grant No. SCEON 695343). The authors thank Seyedeh Mahsa Kamali for useful discussions on reactive ion etching, Sophie Meuret and Toon Coenen for assistance with CL spectroscopy, and Femius Koenderink for useful discussions. We thank the Kavli Nanoscience Institute at Caltech for cleanroom facilities and the AMOLF NanoLab Amsterdam for cathodoluminescence spectroscopy facilities. X. N. and A. K. acknowledge that numerical calculations were supported by the National Science Foundation (DMR-1809915). A. K. and A. A. acknowledge support by the National Science Foundation (EFRI-1641069). Competing financial interest: A. P. is co-founder and co-owner of Delmic BV, a company that produces commercial cathodoluminescence systems like the one that was used in this work.

Attached Files

Published - PhysRevLett.122.117401.pdf

Supplemental Material - supp.pdf


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August 19, 2023
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