Emission of terahertz (THz) radiation as a result of optical rectification of intense femtosecond laser pulses on thin gold films has been studied by time-domain THz spectroscopy. The THz amplitude was measured as a function of film thickness and incidence angle. The experiments reveal that the emitted THz field is suppressed for a thickness below 100 nm, which gives evidence of the nonlocal character of the response. The variation of incidence angle allows us to estimate the components of susceptibility tensor chi^(2) _ijk. For thicker films and near grazing incidence, the emitted THz field attains a peak value of 4 kV/cm.
© 2005 Optical Society of America
Filip Kadlec, Petr Kuzel, and Jean-Louis Coutaz, "Study of terahertz radiation generated by optical rectification on thin gold films," Opt. Lett. 30, 1402-1404 (2005)