High-frequency electrical pulse generation using optical rectification in bulk GaAs

We present the realization of a traveling-wave electrical pulse generator using pure nonresonant instantaneous optical rectification in bulk GaAs. The optical excitation was achieved by far-infrared pulses of 1-6 ps duration in the wavelength range from 8 to 15 mu m, generated by a free-electron laser. The coupling of the optical rectification polarization into the fundamental mode of the microstrip transmission line is verified by angle-resolved measurements. Since optical femtosecond pulses are now becoming readily available, this alternative technique, which gains in efficiency at shorter pulses, may find growing importance for ultrafast pulse generation. (C) 2000 American Institute of Physics. [S0003-6951(00)01419-4].