Semiconductor dynamic aperture for near-field terahertz wave imaging

We describe and discuss near-field terahertz wave imaging with a dynamic aperture created on a semiconductor wafer. The spatial resolution of a near-field terahertz wave imaging system with a dynamic aperture created on a GaAs wafer is determined by the diameter of the gating-beam-induced thin photocarrier layer. With a dynamic aperture created on a GaAs wafer, we have achieved a subwavelength spatial resolution of /spl sim//spl lambda//10. In addition, near-field terahertz wave imaging with a dynamic aperture overcomes the limitations in the reported methods of near-field terahertz wave imaging. Particularly, it is free of the high-pass filtering effect. Various terahertz images are presented to show the possible applications.