We design and experimentally demonstrate an ultrashort integrated polarization splitter on silicon-on-insulator (SOI) platform. Our polarization splitter uses a hybrid plasmonic waveguide as the middle waveguide in a three-core arrangement to achieve large birefringence, allowing only transverse-magnetic (TM) polarized light to directionally couple to the cross port of the directional coupler. Finite-difference time-domain (FDTD) and eigenmode expansive (EME) calculations show that the splitter can achieve an extinction ratio of greater than 15 dB with less than 0.5 dB insertion losses. The polarization splitter was fabricated on SOI platform using standard complementary metal-oxide-semiconductor (CMOS) technology and measured at telecommunications wavelengths. Extinction ratios of 12.3 dB and 13.9 dB for the transverse-electric (TE) and TM polarizations were obtained, together with insertion losses of 2.8 dB and 6.0 dB.

We introduce far-infrared graphene plasmonic crystals. Periodic structural perturbation-in a proof-of-concept form of hexagonal lattice of apertures-of a continuous graphene medium alters delocalized plasmonic dynamics, creating plasmonic bands in a manner akin to photonic crystals. Fourier transform infrared spectroscopy demonstrates band formation, where far-infrared irradiation excites a unique set of plasmonic bands selected by phase matching and symmetry-based selection rules. This band engineering may lead to a new class of graphene plasmonic devices.

Two-dimensional transition metal dichalcogenides (TMDCs) have properties attractive for optoelectronic and quantum applications. A crucial element for devices is the metal–semiconductor interface. However, high contact resistances have hindered progress. Quantum transport studies are scant as low-quality contacts are intractable at cryogenic temperatures. Here, temperature-dependent transfer length measurements are performed on chemical vapor deposition grown single-layer and bilayer WS2 devices with indium alloy contacts. The devices exhibit low contact resistances and Schottky barrier heights (∼10 kΩ μm at 3 K and 1.7 meV). Efficient carrier injection enables high carrier mobilities (∼190 cm2 V–1 s–1) and observation of resonant tunnelling. Density functional theory calculations provide insights into quantum transport and properties of the WS2–indium interface. Our results reveal significant advances toward high-performance WS2 devices using indium alloy contacts.

The bid for scalable physical qubits has attracted many possible candidate platforms. In particular, spin‐based qubits in solid‐state form factors are attractive as they could potentially benefit from processes similar to those used for conventional semiconductor processing. However, material control is a significant challenge for solid‐state spin qubits as residual spins from substrate, dielectric, electrodes, or contaminants from processing contribute to spin decoherence. In the recent decade, valleytronics has seen a revival due to the discovery of valley‐coupled spins in monolayer transition metal dichalcogenides. Such valley‐coupled spins are protected by inversion asymmetry and time reversal symmetry and are promising candidates for robust qubits. In this report, the progress toward building such qubits is presented. Following an introduction to the key attractions in fabricating such qubits, an up‐to‐date brief is provided for the status of each key step, highlighting advancements made and/or outstanding work to be done. This report concludes with a perspective on future development highlighting major remaining milestones toward scalable spin‐valley qubits.