Roadmap on chalcogenide photonics

Alloys of sulfur, selenium and tellurium, often referred to as chalcogenide semiconductors, offer a highly versatile, compositionally-controllable material platform for a variety of passive and active photonic applications. They are optically nonlinear, photoconductive materials with wide transmission windows that present various high- and low-index dielectric, low-epsilon and plasmonic properties across ultra-violet, visible and infrared frequencies, in addition to an, non-volatile, electrically/optically induced switching capability between phase states with markedly different electromagnetic properties. This roadmap collection presents an in-depth account of the critical role that chalcogenide semiconductors play within various traditional and emerging photonic technology platforms. The potential of this field going forward is demonstrated by presenting context and outlook on selected socio-economically important research streams utilizing chalcogenide semiconductors. To this end, this roadmap encompasses selected topics that range from systematic design of material properties and switching kinetics to device-level nanostructuring and integration within various photonic system architectures.