Subpicosecond electrical pulse generation by edge illumination of silicon and indium phosphide photoconductive switches

Using a femtosecond pulsed laser, ultrafast electrical pulses were optoelectronically generated on silicon and indium phosphide by edge illumination of a coplanar transmission line. Backing up theory with experiment, we demonstrate that this pulse-generation method is material independent, thus providing a powerful tool for broadband characterization of devices made on a wide range of semiconductor substrates. We also demonstrate that edge illumination enables the generation of 550 fs electrical pulses on indium phosphide and 800 fs pulses on silicon—the fastest pulses to date on bulk silicon.