Tunable terahertz plasmonic lenses based on semiconductor microslits

A theoretical investigation of tunable terahertz (THz) plasmonic lenses on the basis of InSb microslits is presented.First, it is demonstrated that the surface plasmon polaritons propagating in an InSb microslit array with variant slit widths would face different phase retardations, which, by design, can produce a focusing wavefront. The extraordinary transmission of THz radiation through the InSb subwavelength slit array is also observed. Second, a method for tuning the focal lengths of InSb plasmonic lenses is proposed. The results in this article provide a potential way to realize a tunable terahertz plasmonic lens with high transmission, which can be applied to the application of rapid 3D z‐scanning based THz imaging and sensing.