Terahertz Switch Using an Array of Subwavelength Metallic Holes-coupled-disks

Broadband switching of terahertz waves at room temperature is demonstrated using a reconfigurable subwavelength metallic hole coupled disk array. The interaction between a metallic membrane featuring periodically arranged circular holes and a substrate bearing a correspondingly periodic array of metallic disks - precisely aligned at their centers - significantly enhances the light coupling within each individual metallic structure, leading to an improved optical transmission and the appearance of a new transmission peak. By mechanical displacement of the metallic membrane with respect to the substrate with metallic disks, the light transmission through the structure can be reconfigured. The device exhibits a polarization-insensitive high-contrast switching performance of 89.4 dB at 942 GHz. The full-width at half-maximum bandwidth of the switch is 288 GHz. By proper design of the device's geometric dimensions, the operation frequency and bandwidth of the switch can be scaled.