Impact of Transforming Interface Geometry on Edge States in Valley Photonic Crystals

We investigate how altering the interface geometry from a zigzag to a glide plane interface between two topologically distinct valley Hall emulating photonic crystals (VPC), profoundly affects edge states. We experimentally observe a transition from gapless to gapped edge states, accompanied by the occurrence of slow light within the...

Breakdown of Spin-to-Helicity Locking at the Nanoscale in Topological Photonic Crystal Edge States

We measure the local near-field spin in topological edge state waveguides that emulate the quantum spin Hall effect. We reveal a highly structured spin density distribution that is not linked to a unique pseudospin value. From experimental near-field real-space maps and numerical calculations, we confirm that this local structure is essential...

Topological Protection in Radiative Photonic Crystal Cavities

We study the signatures of topological light confinement in the leakage radiation of two-dimensional topological photonic crystal cavities that feature the quantum spin Hall effect at telecom wavelengths. The mode profiles in real and momentum space are retrieved using far field imaging and Fourier spectropolarimetry. We examine the scaling...

Interplay of Leakage Radiation and Protection in Topological Photonic Crystal Cavities

The introduction of topological concepts to the design of photonic crystal cavities holds great promise for applications in integrated photonics due to the prospect of topological protection. This study examines the signatures of topological light confinement in the leakage radiation of 2D topological photonic crystal cavities. The cavities are...

Direct quantification of topological protection in symmetry-protected photonic edge states at telecom wavelengths

Topological on-chip photonics based on tailored photonic crystals (PhCs) that emulate quantum valley-Hall effects has recently gained widespread interest owing to its promise of robust unidirectional transport of classical and quantum information. We present a direct quantitative evaluation of topological photonic edge eigenstates and their...

LoRaWAN Class B Multicast Scalability

LoRaWAN has emerged as a popular IoT commu- nications technology. It comes with three classes of operation: A, B, and C. Although many IoT use-cases, like Firmware-over- the-Air updates, require multicast, Class A cannot be used for that purpose. Class C can, but consumes a lot of energy. This leaves Class B. In this paper, we investigate Class...