Local Enhancement of Terahertz Waves in Structured Metals

Strong enhancement of electromagnetic (EM) fields is at the core of optics research as higher EM intensity is essential in various nonlinear applications, and, particularly, in the field of terahertz (THz) optics where photon energy is relatively low. In this review, we discuss THz wave interaction with various types of structured metals that results in strong local enhancements of THz fields. Specifically, we consider the aperture-type, the rod-type, and the hybrid type metamaterial systems and explain the analytic nature of local enhancements.