Several years ago THz spectroscopy was brought to my attention
as an emerging field for research and application. While it may
be years in the future when WiFi routers and cellphones use THz,
recent work points to medical imaging and security screening
Photonics reported making plasmonic filters with inkjet printers
for telecommunication signal enhancement. A site to
learn more about THz domain is the RPI Center.
Metamaterials are fabricated materials not present in nature
designed to have specific properties based on their structure.
Work on these fabricated materials is interdisciplinary and
is undergoing development in correlating linear and
nonlinear properties. Emerging devices will make use
of higher order harmonic generation.
Wireless internet hotspots are reported to be
organized with LED light fixtures that have cost and
reliability advantages over WiFi in certain environments.
Test kits are available from the Fraunhofer institute
that is creating visible light communication systems.