Invited Paper
Radiation Control with Gap Surface Plasmons

Gap surface plasmons (GSPs) supported by metal-insulator-metal (MIM) configurations are well suited for the design of efficient and compact (subwavelength-sized) plasmonic resonators that can be realized by structuring the top metal layer supported by a continuous dielectric-metal layered substrate [1]. We have previously shown that MIM nanostructures, in which the top layer consists of a periodic array of nanobricks supporting GSP resonances, offer improved control of the phase of the reflected light [2], thereby allowing one to design efficient and background-free (i.e., no diffraction and no scattering into other polarizations) phase-gradient metasurfaces. Our recent work on GSP-based phase-gradient metasurfaces demonstrated the possibility of realization of various efficient optical components, such as polarization-controlled beam deflectors [3] and surface plasmon couplers [4], which do not conventional counterparts.

In this talk, after briefly reviewing the main recent results [2-4], new developments targeting practical realization of more sophisticated manipulations of reflected light phase and amplitude (such as needed for optical analog computing) will be presented [5]. The GSP-based resonators will then be considered from the viewpoint of interactions of individual quantum emitters (QEs) with GSP resonators, emphasizing that this interaction results in QE relaxation dynamics, free-space radiation patterns and directionality of associated SPP excitation being strongly influenced on the QE position and orientation. Finally, engineering of gold photoluminescence by making use of salient features of (gold-based) GSP resonators is discussed, demonstrating experimentally the possibilities for strong enhancement, wavelength tunability and polarization selectivity of photoluminescence with dedicated design of GSP resonators.

[1] M. G. Nielsen, D. K. Gramotnev, A. Pors, O. Albrektsen, and S. I. Bozhevolnyi, ”Continuous layer gap plasmon resonators,” Opt. Express 19, 19310 (2011).

[2] A. Pors and S. I. Bozhevolnyi, “Plasmonic metasurfaces for efficient phase control in reflection,” Opt. Express 21, 27438 (2013).

[3] A. Pors, O. Albrektsen, I. P. Radko, and S. I. Bozhevolnyi, “Gap-plasmon based metasurfaces for total control of reflected light,” Scientific Reports 3, 2155 (2013).

[4] A. Pors, M. G. Nielsen, T. Bernardin, J.-C. Weeber, and S. I. Bozhevolnyi, “Efficient unidirectional polarization-controlled excitation of surface plasmon polaritons,” Light: Science & Applications 3, e197 (2014).

[5] A. Pors, M. G. Nielsen, and S. I. Bozhevolnyi, “Analog computing using reflective plasmonic metasurfaces,” Nano Lett., 2014, in press.

seib@iti.sdu.dk