FDTD study of a novel terahertz emitter with electrical field enhancement using surface plasmon resonance

In this work, the finite-difference time-domain (FDTD) technique is used to study novel terahertz (THz) emitter structures. The proposed THz antenna requires less pump power of the femtosecond laser pulse whilst provides higher THz output power. This is achieved by the enhancement of the localized electric field in the THz emitter This electric field enhancement is found to have two origins: One is owing to the enhancement of the static electric field of the bias voltage, and the other is the enhancement of the electric field of the incoming femtolaser pulse. The latter enhancement is caused by the interaction of the pump laser and the surface plasmon resonance at the conical gold structure of the photoconductive emitter. This new terahertz emitter could lead to new applications where high-power and broadband terahertz sources are needed.