Simultaneous realization of transmission enhancement and directional beaming of dual-wavelength light by a metal nanoslit

Transmission enhanced dual-wavelength light beaming is realized by a dielectric-metal-dielectric structure. Guided-mode resonance theory is used on the dielectric grating flanked single nanoslit in an optically thick metal to predict the original structure parameters for transmission enhanced dual-wavelength (442 nm and 633 nm) light beaming. Finite-difference time-domain numerical simulations confirm the theoretical prediction and demonstrate that the normalized-to-area transmittance of 10.8 and 14.7 and beaming angle of 2.40 degrees and 2.65 degrees for 442 nm and 633 nm, respectively, are achieved with a single structure, suggesting the potential applications of such structures in optical data storage, nanoscale wavelength multiplexing, directional light sources and emitters. (C) 2009 Optical Society of America