The detection properties of a chalcopyrite zinc germanium diphosphide (ZnGeP2, ZGP) electro-optic (EO) crystal, having thickness of 1080 μm and cut along the <012> plane, is studied in the terahertz (THz) frequency range. Outstanding phase matching is achieved between the optical probe pulse and the THz frequency components, leading to a large EO detection bandwidth. ZGP has the ability to measure frequencies that are 1.3 and 1.2 times greater than that of ZnTe for crystal thicknesses of 1080 and 500 μm, respectively. Furthermore, the ZGP crystal is able to detect frequency components that are ≥4.6 times larger than both ZnSe and GaP (for crystal thicknesses of 1080 μm) and ≥2.2 times larger than ZnSe and GaP (for crystal thicknesses of 500 μm).
The relative permittivity (real and imaginary component), absorption coefficient, and loss tangent of various cellulose nanocrystal (CNC) films, a dissolving pulp film, and a CNC powder are obtained by performing terahertz (THz) transmission spectroscopy experiments. The CNC films are constructed using different drying techniques (i.e. air-drying and freeze-drying) and are made from CNCs that have been extracted from various sources (i.e. hardwood, softwood, and dissolving pulp). Between frequencies of 0.2 and 1.5 THz, the real component of the permittivity is seen to range from 1.8-3.3 for the CNC films, suggesting that both the drying technique and CNC source material influence this dielectric property. Importantly, the CNC films are shown to exhibit relatively small THz absorption and loss tangent properties, such that CNC-based dielectric mirrors, waveguides, and transistors may be achieved.