In this contribution, we present the direct comparison between Ophir Pyrocam IV and Terasense Tera-1024 cameras used for imaging of terahertz (THz) and sub-THz signals. We compare general properties, such as frequency dependent and polarisation dependent sensitivity, angle dependent sensitivity essential for holographic and noncollinear interferometric measurements, and draw a conclusion about the most suitable camera for the discussed imaging approaches. Both cameras show acceptable performance and sensitivity at imaging both 0.14 THz and 0.3 THz signals. The Terasense camera, expectedly, shows stronger polarisation dependent properties, however, is significantly more angle independent, showing an acceptable performance at all tested incident angles up to 50 degrees. At the same time, although the angle dependence is stronger for the Ophir camera, it has smaller pixel pitch and more extended post-processing features, thus making it somewhat better suited for noncollinear interferometric and holographic sub THz imaging.
A swept-source optical coherence tomography (OCT) system is demonstrated in the mid-infrared region. A Michelson interferometric setup is illuminated by an external cavity quantum cascade laser (QCL), with a scanning frequency of 1 Hz. A-scans were collected using three different samples: a mirror, CaF2 coated with germanium on both of its surfaces, and CaF2 coated with germanium on the back side of the sample. These depth-profiles were used to mimic a tissue sample with multiple reflective boundaries. Fourier transformation of these interference fringes clearly showed the expected depths of reflection, allowing for the signal to noise ratio of the system to be determined.