LFI-based confocal imaging system characterisation

The datasets comprise measurements of a confocal imaging setup with a THz quantum cascade laser acting as source, detector, and pinhole via laser feedback interferometry (LFI). The optical system is fully characterised by performing beam profile measurements with a pyroelectric detector at different stages of the system. The point-spread function of the LFI-based system is measured, via a knife-edge technique, and compared to the point spread function of a conventional imaging configuration utilising a pyroelectric detector. Different focusing numerical apertures are employed for which beam profiles, axial signal distribution, and imaging of resolution targets are performed. Finally, 3D tomography imaging of a printed circuit board is conducted to test the system's performance.