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. (c) 2008 American Institute of Physics.