Generation of elliptically polarized half-cycle terahertz pulses generated by 6H-SiC large aperture photoconductive antenna

We demonstrate the generation of half-cycle terahertz pulses with elliptical polarization and 167 nJ pulse energy. These pulses have been generated using a 6H-SiC Large Aperture Photo-conductive Antenna (LAPCA) covered with a binary phase mask and excited by a 400 nm laser. We show that by changing the thickness of the phase mask and the geometry of the LAPCA it is possible to generate intense half-cycle terahertz pulses with circular polarization.