Deep subwavelength manipulation of THz waves by plasmonic surface

Deep subwavelength manipulation of terahertz (THz) wave is a key method to realize compact on chip THz devices. It is demonstrated that the refractive index change in a deep subwavelength region of a dielectric layer can effectively manipulate the surface THz wave propagation by the simulation study. The feature size of this area is only 10 μm (∼1/8 λ). A slight change of refractive index, position or size of this region is enough to manipulate the surface THz waves with high efficiency, such as the transmissivity or reflectivity of different THz frequencies. Moreover, the change of the deep subwavelength region can be controlled by an ultrafast laser to achieve ultrafast dynamic manipulation of THz waves. This is a concise and efficient method of manipulating electromagnetic waves on the deep subwavelength scale and to fabricate more compact integrated optical devices.