Efficient outcoupling of surface-plasma waves to radiation modes by use of dielectric diffraction gratings on a flat metallic surface is discussed. The dielectric gratings, which have a surface-relief structure with only several tens of nanometers in peak-to-trough height on a flat metal surface, can efficiently extract radiation modes propagating in free space from the surface-plasmon modes. An outcoupling efficiency of 50% is estimated with the rigorous coupled-wave diffraction theory, and it is confirmed by the experiment.
© 2003 Optical Society of America
Suntak Park, Gwansu Lee, Seok Ho Song, Cha Hwan Oh, and Pill Soo Kim, "Resonant coupling of surface plasmons to radiation modes by use of dielectric gratings," Opt. Lett. 28, 1870-1872 (2003)