THz Imaging Using a Quantum-Well Photodetector with Background Limited Performance

Terahertz (THz) quantum well photodetectors (QWPs) are an extension of quantum well infrared photodetectors in the THz region. We construct an imaging system based on a THz QWP with a narrow response range from 3 THz to 6 THz. The peak responsivity of the THz QWP having background-limited performance is about 0.5 A/W, and the corresponding detectivity reaches 10¹¹cm?Hz^1/2/W at temperature of 4.2 K. We obtain the images of a concealed object by the imaging system and prove that THz QWPs have the potential for imaging applications.