It is good to point out that there is much talk about researchers working at THz frequencies, but in actuality, most are working in the mm-wave and sub-THz/sub-mmwave bands (30 GHz to 300 GHz is defined as the mm-wave band, 300 GHz and higher is the sub-mm-wave). The bulk of the research today is below 300 GHz, due to the current availability of test equipment and pricing. Only a small group worldwide are really working at the THz frequencies.
Currently, Virginia Diodes (VDI), located where else but Virginia, makes the THz converters for Agilent's Vector Network Analyzers. Most of their business comes from the radio astronomy, JPL and device characterization community. For instance, Northrop-Grumman in SoCal is working with VDI for on-wafer transistor device measurements. I believe NGC has reached record-breaking Ft's of greater than 700 GHz.
Some of the popular research at the sub-THz frequencies are for radiometry, atmospheric and space-based imaging, explosives detection and radio astronomy. Due to the naturally occuring resonant frequencies, some very interesting research going on with regards to imaging! I had a chance to attend the THz Conference in May in Tucscon, AZ, and though it was called the "THz Conference," again most of the work was below 600 GHz.
@Barry, too bad you couldn't attend the Crab Feast in Baltimore last week...crab cakes were excellent!
On the questions of benefits and costs, much of the work that is being done in the THz region is aimed at improving our safety and security, through the development of high resolution imaging systems as well as through more controlled processes for the development of medication by understanding of the chemical composition. In addition with the development of active components at the higher frequencies there is a growing need for users to better understand the harmonic behavior of the components for a 100 GHz 3rd harmonic behavior will drive the need for at least 325GHz. It is clear that as the technology evolves from a development and usage side the need will drive the cost down.
I have always been intrigued by the potential to exploit the vast frequency range between electrical (sub-THz) and optical (hundreds of THz) frequency band.
These bands will definitely be converging in the coming years and decades, but today they are covered by vastly different engineers and engineering disciplines.
At what point does optics meet electonics?
Tera hertz waves penerate through lot of materials without any destruction. So this is being tried in many applications like security systems,biomedical,pharma,semiconductor and not but the least broad band communications.