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Terahertz waves offer a profound platform for next-generation sensing, imaging, and information communications. However, all conventional terahertz components and systems suffer from a bulky design, sensitivity to imperfections, and transmission losses. Here, we propose and experimentally demonstrate on-chip integration and miniaturization of topological devices which may address many existing drawbacks of the terahertz technology. We design and fabricate topological devices based on valley-Hall photonic structures that can be employed for various integrated components of on-chip terahertz systems. More specifically, we demonstrate the valley-locked asymmetric energy flow and mode conversion with topological straight waveguide, multi-port couplers, wave division, and whispering gallery mode resonators. Our devices are based on topological membrane metasurfaces which are of great importance for developing on-chip photonics and bringing many novel features into terahertz devices.

Supplemental Material for Surface-Enhanced Raman Scattering (SERS) Studies of Disc-on-Pillar (DOP) Arrays: Contrasting Enhancement Factor with Analytical Performance by Raymond A. Velez, Nickolay V. Lavrik, Ivan I. Kravchenko, Michael J. Sepaniak and Marco A. De Jesus in Applied Spectroscopy

Supplementary Information

Supplementary Information

This file contains extra details regarding metasurface simulations and fabrication

Metasurface analogues of electromagnetically induced transparency (EIT) have been a major focus of the nanophotonics field over the past several years due their ability to produce high quality factor (Q-factor) resonances for applications such as low-loss slow light devices and highly sensitive optical sensors. However, Ohmic loss limits the achievable Q-factors in conventional plasmonic EIT metasurfaces to values less than 10, significantly hampering device performance. Here, we report experimental demonstration of a classical analogue of EIT using all-dielectric silicon-based metasurfaces. Due to extremely low absorption loss and coherent interaction of neighboring meta-atoms, a record-high Q-factor of 483 is experimentally observed, leading to a refractive index sensor with a figure-of-merit (FOM) of 103. Furthermore, we show that the dielectric metasurfaces can be engineered to confine the optical field in either the silicon resonator or the environment, allowing one to tailor light-matter interaction at the nanoscale., Comment: Two errors have been corrected: 1. In the simulations, cross-polarized fields were mistakenly not included leading to artificially inflated Q-factors. 2. The measured arrays were later found to have a partially connected gap, preventing cross-polarized light scattering and preserving a high Q-factor. The new manuscript corrects these errors and examines fully connected ring-based resonators