Abstract
Terahertz (Thz) technology makes possible imaging of phenomena, inaccessible to visible light, but suffers from speckles, produced by coherent sources. This problem is of special importance for THz imaging, because surface roughness is closer to the object dimension as in optical imaging. Here we proposed a phase diversity Hadamard solution for speckle-free imaging with a coherent beam. First the Hadamard principle has been proven by experimental conversion of the sum of electrical THz fields (coherent) into a sum of intensities (incoherent). Then Hadamard diffusers of two different geometries have been designed, built and tested. Speckle reduction was measured using W-band (75-110 GHz) free-space measurement setups.
