Novel THz imaging array using high resistivity metasurfaces

In this paper, lossy metasurfaces are employed in the design of uncooled terahertz (THz) bolometers on polymer substrate. The metasurface bolometer is composed of a metal backed low loss dielectric substrate and thin patterned lossy metal layer. Numerical simulations using finite element method (FEM) are carried out to design optimal unit cells with high absorptivity. An array of these unit cells are combined together to form a pixel element of an imaging array. Unit cells with center frequency of 0.1 and 0.4 THz are designed. A 3×3 imaging array operating at 0.1THz is fabricated on a plastic substrate and measured results are presented. An image of a concealed object inside a paper envelope is also demonstrated in transmission mode using this array. Results show that high sensitivity THz bolometers can be fabricated on low-cost substrates using strongly absorbing metasurfaces.