Electro-optically tunable compact terahertz source

The promise of terahertz technology for surveillance and reconnaissance applications is huge. Despite the technical advantages, the major challenge today in terahertz technology is the development of a portable high-power terahertz source. Of the several available terahertz source technologies those based on the difference frequency technique are very promising, as they can produce a relatively high power terahertz beam over the frequency from 100 GHz to 3.5 THz, which is tunable. However, earlier this technique suffered from a high loss of terahertz signal, and produced a weak terahertz beam, in part due to a large impedance mismatching. Also its frequency tuning was cumbersome and its tuning range was limited since it was typically performed by rotating a nonlinear optical crystal against the pumping beam. In our recent experiments we modified the technique to improve the impedance matching and to replace the mechanical tuning with an electro-optical tuning. With this new technique we demonstrated a terahertz beam output power exceeding 10 mW (occasionally $\sim $ 100 mW) at frequencies around 1 THz. Our new technique the frequency tuning is very convenient and not limited by the geometry of the experimental set up. Detailed experiments and experimental results will be discussed