Sub-picosecond photoconducting dipole antennas.

Photoconducting antennas have been demonstrated which are capable of generating and coherently detecting subpicosecond electrical pulses. These antennas, when illuminated with femtosecond optical pulses, radiate electrical pulses which have frequency spectra that extend from 100 GHz to > 2 THz. Microscopic dipoles measuring 50, 100, and 200microns have been fabricated and tested. Integrated photoconductors of radiation-damaged silicon- on-sapphire were used both for impulsive current excitation of the transmitting antennas as well as for gating the receiving antennas.