Absolute Spectral Responsivity Calibration of Terahertz Detector

Calibrating the absolute spectral responsivity is of great importance, because this guides the design and application of terahertz detectors. In this paper, we build a calibration system, and this system can be used to calibrate absolute spectral responsivity of terahertz detectors at a serial of frequencies such as 0.84, 1.63, 2.52, 4.25 THz et al. The key components of the system include a standard terahertz detector and a terahertz gas laser, and other components such as TPX lens and ultrasensitive voltmeter are also included. The calibration system was employed to calibrate a terahertz detector with the model of 12D-3S-VP produced by Gentec Inc., and the absolute spectral responsivity of 193.8 mV/W at 2.52 THz was obtained. The measurement uncertainty is analyzed to be 6.0%. This work not only offers method and system to terahertz detector calibration, but also contributes to high accuracy terahertz power measurement and terahertz device calibration.