Study of terahertz radiation generated by optical rectification on thin gold films

Abstract

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 ?ijk(2). For thicker films and near grazing incidence, the emitted THz field attains a peak value of 4?kV?cm.