Active Multipixel Photoconductive Emitter Technology for THz Beam Shaping and Steering

A multipixel photoconductive emitter which consisted of an array of interdigitated electrodes was used to electrically control the spatial profile of a THz beam. We demonstrated that by varying the applied voltage levels, it is possible to spatially modulate the THz beam, with shapes tunable from gaussian to arbitrary non-gaussian shapes, such as a top hat. We characterized the THz beam profile at different off-axis transverse positions to validate the beam steering capability of our device. The spatial resolution of the approach was determined for different THz frequencies and the diffraction-limited performance of the system was established by comparison with the Abbé and Sparrow criteria.