Continuous and Pulsed THz generation with molecular gas lasers and photoconductive antennas gated by femtosecond pulses

TeraHertz waves, associated with the far-infrared region of the electromagnetic spectrum, are gaining increasing interest in the past years due to promising applications in imaging, spectroscopy, and even communications. Here we report THz generation based on two systems: 1) continuous-wave (cw) laser generation in molecular gas lasers, and 2) short pulse generation in photoconductive antennas, gated by femtosecond near-infrared Ti:sapphire lasers. With the first system, we have generated tens of monochromatic CW laser lines over the last years, extending roughly from 40 microns to several hundred microns. This is done by optical pumping of gas lasers based on polar molecules such as methanol and its isotopes. In the second system, under development, pulsed THz radiation is generated by a photoconductive antenna built in a semi-insulating GaAs substrate excited by femtosecond pulses from a near-infrared (800 nm) Ti:sapphire laser.