Review on broadband terahertz blackbody calibration sources

Abstract Terahertz radiometers are widely used in fields such as radio astronomy, remote sensing, and atmospheric observation, where accurate measurements rely on high-precision calibration blackbody radiation sources. This review focuses on key technologies for enhancing the brightness temperature accuracy of terahertz blackbody sources, including the structural design of the radiation source and the optimization of terahertz absorbing materials. First, the fundamental theory of blackbody radiation and its role in terahertz calibration are systematically introduced. Then, two main structural types—cavity-type and wide-aperture blackbodies—are discussed in terms of design principles, performance characteristics, and recent research progress. Finally, the review summarizes advances in terahertz absorbing materials, highlights current design strategies, and explores their application potential in blackbody calibration sources. This work aims to provide a comprehensive overview of the current state and development trends in both structural and material aspects of terahertz calibration blackbody sources, offering theoretical guidance and technical support for the development of high-precision, broadband terahertz calibration systems.