Characterization of photogenerated terahertz radiation in high-T/sub c/ superconductors

The characteristics of photogenerated terahertz (THz) pulses radiation about 450 fs wide from a current-biased superconducting YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// (YBCO) bow-tie antenna were investigated using a free-space electro-optic sampling technique. The dynamics of the quasiparticles optically induced by the ultrafast laser pulse primarily determines the performances of the transient THz radiation generated under different operating parameters are discussed.