Terahertz transmission in subwavelength holes of asymmetric metal-dielectric interfaces: The effect of a dielectric layer

The influence of a dielectric thin film on resonant transmission of terahertz pulses in a plasmonic array of subwavelength holes of asymmetric dielectric-metal interfaces is presented. A giant tuning of up to 0.80 THz at the surface plasmon metal-air [±1,0] mode at 1.95 THz and a further enhanced transmission at the metal-Si [±1,0] mode at 0.5 THz are achieved by modifying the film thickness. The experimental results are characterized by numerical simulation based on finite element method and angle-dependent measurements. The sensitive nature in the plasmonic hole array of asymmetric interfaces is promising in applications of biochemical sensing and tunable integrated plasmonic devices.