Abstract
To realize reliable terahertz sensing applications, accurate calibration of sources and detectors is
essential. Since power is a basic physical quantity, its absolute measurement is important to evaluate the
performance of the sensors. This paper reviews recent international trends in terahertz power
measurements and standards. A highly sensitive calorimeter is introduced to measure absolute terahertz
power below microwatt levels at room temperature. The calorimeter measures the absolute terahertz
power by substituting dc power using an isothermal calorimetric technique. A power meter is calibrated
using the calorimeter as a reference standard. This calorimeter is expected to realize the International
System of Units (SI)-traceable measurements of terahertz power.
