摘要
Lying between radio frequency and infrared radiation, terahertz （THz） wave encounters lots of difficulties to produce, detect, transmit, and modulate. Great efforts have been made to construct THz devices, including sources, detectors, switches, modulators, lenses, and filters. However, only moderate progresses have been made in THz generation and detection. Furthermore, the devices and techniques to control and manipulate THz waves are still in its infancy. Therefore, it is still a challenge to date to develop sophisticated THz application systems such as communication, sensing, safety inspection, imaging and medical diagnose systems. This difficult position of THz wave is essential due to the deficiency of THz materials having a suitable THz electromagnetic response, as compared to its neighboring microwave and infrared regime. Practicable material will largely push the THz technology to real-world applications. The GaAs/AlxGa~_xAs material system, for example, is the heart of THz quantum cascade lasers. High quality NbN films, again, set the basis of THz hot electron bolometer.
Lying between radio frequency and infrared radiation, terahertz （THz） wave encounters lots of difficulties to produce, detect, transmit, and modulate. Great efforts have been made to construct THz devices, including sources, detectors, switches, modulators, lenses, and filters. However, only moderate progresses have been made in THz generation and detection. Furthermore, the devices and techniques to control and manipulate THz waves are still in its infancy. Therefore, it is still a challenge to date to develop sophisticated THz application systems such as communication, sensing, safety inspection, imaging and medical diagnose systems. This difficult position of THz wave is essential due to the deficiency of THz materials having a suitable THz electromagnetic response, as compared to its neighboring microwave and infrared regime. Practicable material will largely push the THz technology to real-world applications. The GaAs/AlxGa~_xAs material system, for example, is the heart of THz quantum cascade lasers. High quality NbN films, again, set the basis of THz hot electron bolometer.
