Abstract: A method of obtaining a series of images of a three-dimensional object by transmitting pulsed terahertz (THz) radiation through the entire object from a plurality of angles, optically detecting changes in the transmitted THz radiation using pulsed laser radiation, and constructing a plurality of imaged slices of the three-dimensional object using the detected changes in the transmitted THz radiation. The THz radiation is transmitted through the object as a scanning spot. The object is placed within the Rayleigh range of the focused THz beam and a focusing system is used to transfer the imaging plane from adjacent the object to a desired distance away from the object. A related system is also disclosed.

Abstract: Systems and methods for reconstructing a plurality of images of an object. An exemplary system includes a radiation source adapted to emit radiation at a plurality of frequencies; a lens with frequency-dependent focal length, such as a Fresnel lens, adapted to receive radiation modified by the object and to project onto a fixed image plane a frequency-dependent image of a slice of the object perpendicular to the radiation path; a sensor for capturing the frequency-dependent image of the object; and apparatus for facilitating creation and capture of a plurality of frequency-dependent images of the object at the plurality of frequencies. A system for reconstructing a tomographic image of the object further includes apparatus for assembling the plurality of frequency-dependent images to reconstruct the tomographic image. Methods and systems are described for use in the visible, audible, and THz frequency ranges and with broadband or narrowband radiation sources.