THz beam generation from YBCO thin films using a 1.55 mu m femtosecond laser

High-Tc superconductor (HTS) is a promising material for terahertz (THz) el ectronics, The THz beam generation from YBa2Cu3O7-delta (YBCO) thin film an tennas using femtosecond (fs) laser pulses with a wavelength h of around 1. 55 mum is demonstrated. The mechanism of the THz beam generation is reveale d to be of the one photon excitation process corresponding to an intraband transition in the in-gap state. The properties of the THz beam generation e xcited by the 1.55 mum fs laser are similar to that excited by an 800 nm fs laser.