Terahertz Imaging System with On-Chip Superconducting Josephson Plasma Emitters for Nondestructive Testing

Abstract

Compared with neighboring microwave and infrared bands, terahertz (THz) frequencies offer unique advantages for imaging applications. In particular, characteristic THz spectral fingerprints of chemicals enable nondestructive evaluation and imaging of biological objects, materials, components, electronic circuits, and systems, with broad relevance to security, medical diagnostics, materials science, pharmaceutical inspection, aeronautics, and electronics industries. Despite this potential, practical THz imaging systems have been limited by the scarcity of compact, power-efficient, and tunable THz sources. In this work, we employ high-temperature superconducting monolithic sources - Josephson plasma emitters - as chip-integrated, coherent, monochromatic, and broadly tunable THz wave emitters, and demonstrate nondestructive THz imaging of concealed metallic surgical blades, floppy disks, dandelion leaves, and sliced pork meat. The resulting images exhibit high contrast between metallic and nonmetallic regions, reveal fine structural features of diverse objects, and enable selective visualization of different powdered materials. These results establish the feasibility of a compact THz imaging system based on on-chip superconducting sources for nondestructive, contactless, rapid, and accurate applications in environmental monitoring, security screening, medical diagnostics, materials characterization, and quantum science and technology.