Compact slit-based couplers for metal-dielectric-metal plasmonic waveguides.

We introduce compact wavelength-scale slit-based structures for coupling free space light into metal-dielectric-metal (MDM) subwave-length plasmonic waveguides. We first show that for a single slit structure the coupling efficiency is limited by a trade-off between the light power coupled into the slit, and the transmission of the slit-MDM waveguide junction. We next consider a two-section slit structure, and show that for such a structure the upper slit section enhances the coupling of the incident light into the lower slit section. The optimized two-section slit structure results in ∼ 2.3 times enhancement of the coupling into the MDM plasmonic waveguide compared to the optimized single-slit structure. We finally consider a symmetric double-slit structure, and show that for such a structure the surface plasmons excited at the metal-air interfaces are partially coupled into the slits. Thus, the coupling of the incident light into the slits is greatly enhanced, and the optimized double-slit structure results in ∼ 3.3 times coupling enhancement compared to the optimized single-slit structure. In all cases the coupler response is broadband.

[1]  S. Ramo,et al.  Fields and Waves in Communication Electronics , 1966 .

[2]  Shanhui Fan,et al.  Method for sensitivity analysis of photonic crystal devices. , 2004 .

[3]  Zhaolin Lu,et al.  Nanoplasmonic couplers and splitters. , 2009, Optics express.

[4]  Nicholas A. Melosh,et al.  Efficient optical coupling into metal-insulator-metal plasmon modes with subwavelength diffraction gratings , 2008 .

[5]  E. Glytsis,et al.  Finite-number-of-periods holographic gratings with finite-width incident beams: analysis using the finite-difference frequency-domain method. , 2002, Journal of the Optical Society of America. A, Optics, image science, and vision.

[6]  R. Bansal,et al.  Antenna theory; analysis and design , 1984, Proceedings of the IEEE.

[7]  L. Verslegers,et al.  Temporal coupled-mode theory for resonant apertures , 2010, CLEO: 2011 - Laser Science to Photonic Applications.

[8]  H. Lezec,et al.  Negative Refraction at Visible Frequencies , 2007, Science.

[9]  D. Miller,et al.  Transmission Line and Equivalent Circuit Models for Plasmonic Waveguide Components , 2008, IEEE Journal of Selected Topics in Quantum Electronics.

[10]  Carretera de Valencia,et al.  The finite element method in electromagnetics , 2000 .

[11]  R. Salas-Montiel,et al.  Efficient directional coupling between silicon and copper plasmonic nanoslot waveguides: toward metal-oxide-silicon nanophotonics. , 2010, Nano letters.

[12]  Bernhard Lamprecht,et al.  Non?diffraction-limited light transport by gold nanowires , 2002 .

[13]  Yehia Massoud,et al.  Nanoscale surface plasmon based resonator using rectangular geometry , 2007 .

[14]  Shanhui Fan,et al.  Theoretical investigation of compact couplers between dielectric slab waveguides and two-dimensional metal-dielectric-metal plasmonic waveguides. , 2007, Optics express.

[15]  C. Min,et al.  Microcavity enhanced optical absorption in subwavelength slits. , 2011, Optics express.

[16]  Peter B Catrysse,et al.  Geometries and materials for subwavelength surface plasmon modes. , 2004, Journal of the Optical Society of America. A, Optics, image science, and vision.

[17]  Georgios Veronis,et al.  Slow-light enhanced absorption switches in metal-dielectric-metal plasmonic waveguides , 2009, CLEO: 2011 - Laser Science to Photonic Applications.

[18]  E. Palik.  Handbook of Optical Constants of Solids , 1997 .

[19]  Liesbet Lagae,et al.  Electrical detection of confined gap plasmons in metal-insulator-metal waveguides , 2009 .

[20]  R. Kaul,et al.  Microwave engineering , 1989, IEEE Potentials.

[21]  Merrielle Spain,et al.  Tunable color filters based on metal-insulator-metal resonators. , 2009, Nano letters.

[22]  Toshihiro Okamoto,et al.  Characteristics of gap plasmon waveguide with stub structures. , 2008, Optics express.

[23]  E. Economou.  Surface Plasmons in Thin Films , 1969 .

[24]  Harry A. Atwater,et al.  Local detection of electromagnetic energy transport below the diffraction limit in metal nanoparticle plasmon waveguides , 2003, Nature materials.

[25]  Min Qiu,et al.  Broadband high-efficiency surface-plasmon-polariton coupler with silicon-metal interface , 2009 .

[26]  Kalmanje Krishnakumar,et al.  Micro-Genetic Algorithms For Stationary And Non-Stationary Function Optimization , 1990, Other Conferences.

[27]  M. Orenstein,et al.  Modeling of Complementary (Void) Plasmon Waveguiding , 2007, Journal of Lightwave Technology.

[28]  Shanhui Fan,et al.  Bends and splitters in metal-dielectric-metal subwavelength plasmonic waveguides , 2005 .

[29]  Ruoxi Yang,et al.  Efficient light coupling between dielectric slot waveguide and plasmonic slot waveguide. , 2010, Optics letters.

[30]  Xian-Shi Lin,et al.  Tooth-shaped plasmonic waveguide filters with nanometeric sizes. , 2008, Optics letters.

[31]  T. Ebbesen,et al.  Channel plasmon subwavelength waveguide components including interferometers and ring resonators , 2006, Nature.

[32]  H. Lezec,et al.  Highly confined photon transport in subwavelength metallic slot waveguides. , 2006, Nano letters.