Radiometric sampling system for use in the terahertz band of the electromagnetic spectrum

A new radiometric measuring system to be used in the terahertz region, equipped with a pyroelectric detector and a standard synchronous sampling system is being developed at INRIM. A black-body cylindrical cavity, suitable for operating from -50°C to 80°C with known thermodynamic temperature and calculable radiant flux, is employed as a polychromatic terahertz source for the calibration of the radiometer. Preliminary tests were performed in order to determine the responsivity and stability of the radiometer in function of the incident power density, at a specific spectral band. A relative uncertainty lower than 0.2% is obtained with radiation peak intensity from 15.76 THz to 18.7 THz.