Sub-wavelength THz imaging through optical rectification

Sub-wavelength THz imaging has previously been demonstrated by the optical rectification method, i.e. generating THz waves in the sample [1]. We have rendered the initial experimental setup more practical by using a simple fs laser oscillator and an efficient photo-conducting detector. We thus recorded images, at different THz frequencies with a 41-μm lateral resolution, of a sample made of ZnTe grains, and generated THz peak magnitudes with a 33 μm and 12 μm lateral resolution of a periodically poled KTP crystal.