Enhanced THz radiation from YBCO thin film bow-tie antennas with hyper-hemispherical MgO lens

摘要

We demonstrate power enhancement of terahertz (THz) radiation from YBCO thin films. An ultra-wide-band electromagnetic pulse, which contains frequency components over 3 THz, was excited by ultrafast supercurrent modulation with femtosecond optical pulse irradiation. The maximum THz radiation power emitted into free space was achieved up to 0.5 /spl mu/W with the combination of a bow-tie antenna and an MgO hyper-hemispherical lens. We discuss the radiation power dependence on temperature, excitation power, and bias supercurrent.