4. Glossary

Antenne photoconductrice; photoconducting antenna

Device integrating two metal electrodes deposited on an intrinsic semiconductor substrate. When emitted, these electrodes are biased by a DC voltage. By illuminating the gap between the electrodes with a pulsed laser, the photogenerated carriers in the substrate are accelerated by the applied voltage and radiate a very short-lived (sub-picosecond) electromagnetic signal into space. In detection mode, the device is not polarized, but the carriers are accelerated by the electric field of a concomitantly arriving terahertz signal. The current measured is proportional to this terahertz field.

Frequency beating

Technique for generating a sum or difference of frequencies by illuminating a material or non-linear component with two laser beams of different wavelengths. This...