Experimental time-domain study of THz signals from impulse excitation of ahorizontal surface dipole

Using optoelectronic techniques with sub-ps resolution, we have characteriz ed the electric-field time-domain response from an impulsively excited, mic ron-sized dipole antenna on a dielectric surface. When detected by an adjac ent dipole antenna 400 mu m distant, two primary signals are observed, a fa r-field pulse reflected from the back surface of the substrate and a surfac e-wave pulse. The surface-wave pulse appears as two distinct surface-propag ating pulses despite originating from the dipole simultaneously. (C) 1999 A merican Institute of Physics. [S0003-6951(99)02712-6].