Abstract

The mechanism and potential application to ultrafast optoelectronics of THz radiation excited by ultrashort pulse lasers have been studied intensively. ^1,2 With regard to its mechanism, the THz radiation from semiconductor surfaces has been explained by the dipole induced during the relaxation process of the surface surge current or optical rectification.³ With regard to its application, this phenomena can be a good interface between well-developed ultrafast optics extending to the sub 10-fsec region, and ultrafast electronics around the picosecond region. Additionally, this radiation is an attractive light source for studying time-resolved far-infrared spectroscopy of phonons in solids and gaps of superconductors. For this purpose, the properties of this radiation should be known in detail. In this presentation, we will describe spatial and spectral properties of THz radiation from bulk GaAs excited by ultrashort-laser pulses and the diffraction effects.

© 1995 Optical Society of America