  Compared with adjacent microwaves and infrared frequencies, terahertz (THz)
frequency offers numerous advantages for imaging applications. The unique THz
spectral signatures of chemicals allow the development of THz imaging systems
for nondestructive tests and the evaluation of biological objects, materials,
components, circuits, and systems, which are especially useful in the security,
medical, material, pharmaceutical, aeronautical, and electronics industries.
However, technological advancements have been hindered owing to the lack of
power-efficient and compact THz sources. Here, we use high-temperature
superconducting monolithic sources known as Josephson plasma emitters
(JPEs)-which are compact, chip-integrated coherent and monochromatic sources of
broadly tunable THz waves-and report the art of non-destructive imaging of
concealed metallic surgical blades, floppy disks, dandelion leaves, and slices
of pork meat in the THz spectral range. The quality of the images, exhibiting
high-contrast differentiation between metallic and non-metallic parts, making
different features of objects visible, and targeting different powders,
demonstrates the viability of this THz imaging system for nondestructive,
contactless, quick, and accurate environmental monitoring, security, medicine,
materials, and quantum science and technology applications.
