Polarization state measurement of terahertz electromagnetic radiation by three-contact photoconductive antenna.

We have fabricated a three-contact photoconductive antenna for the polarization-sensitive detection of terahertz electromagnetic radiation. Taking into account all three photoconductive signal current components, this three-contact photoconductive antenna can measure the polarization state of pulsed THz radiation at an accuracy comparable to that achieved using the conventional method which employs a set of wire-grid polarizers. The three-contact photoconductive receiver may be useful for polarization-sensitive spectroscopy such as vibrational circular dichroism spectroscopy and ellipsometry in the THz frequency region.