Transmission terahertz waveguide-based imaging below the diffraction limit

Using a terahertz line source from a near dispersion-free parallel plate waveguide, we demonstrate broad bandwidth imaging at terahertz frequencies with subwavelength image resolution. Terahertz radiation is coupled into a parallel plate waveguide with a 100 mu m plate spacing, which serves as the imaging aperture. The image data are collected as projections and the final image is reconstructed using the filtered back-projection algorithm, similar to that in x-ray computed tomography. Images taken using a waveguide-based line source demonstrate higher resolution than can be achieved using a confocal cylindrical lens setup. (c) 2005 American Institute of Physics.