4. New digital treatments

4.1 Holography

Terahertz (THz) holographic imaging is a forward-looking approach to lens-free visualization. It is of great interest thanks to its simple experimental configuration and image reconstruction capability in digital post-processing mode, as well as its higher resolution than conventional THz imagers. One of the last mastered frequencies in the electromagnetic spectrum, the THz band presents great opportunities for the introduction of modern imaging. THz holographic imaging, operating at fixed frequencies with CW sources, provides no spectral information, but uses simple, compact and cost-effective equipment. As with the visible range of the electromagnetic spectrum, digital terahertz holography enables phase information to be recovered from intensity distributions. Phase...