Plasmonic structures are an advantageous alternative to photonic structures due to their capabilities to operate at dimensions bellow the diffractive limit and strong radiation confinement. Moreover, plasmonic metasurface are the perfect option for beam shaping at nanoscale and are presently used for flat optical components [1,2], biosensors [3], solar cells and photodetectors [4,5]. This type of structures are composed of an array of metallic nano-antennas patterned on a dielectric substrate [6] and offers the possibility of beam shaping due to the plasmonic nano-antennas exceptional advantages to sustain magnetic and electric resonances [7].
We present a method for modeling the plasmonic metasurfaces to obtain a phase shift of electromagnetic radiation that propagates through a plasmonic metasurface from 0 to π rad or 2π rad. Therefore, by dividing the nano-antennas that form the array in tow periodic successions of a various number of elements with different sizes we can achieve the desired results. Furthermore, the phase manipulation can be achieved also by modeling the configuration of the nano-antennas on the selected substrate. Due to the importance of a proper defined geometry for the metallic (gold) structures in this type of study, we present an ample 3D numerical investigation using finite differential time domain (FDTD) method of both cylindrical and rectangular resonators patterned on glass or silicon. Fig.1 presents the phase behavior when the electromagnetic radiation propagates through described plasmonic metasurface.
References:
[1] Yiting Yu, Hans Zappe, Optics Express 19, pp. 9434-9444 (2011)
[2] Francesco Aietaet al., Nano Lett. 12 ( 2012), pp 4932–4936
[3] Alexandre G. Brolo, Nature Photonics 6, 709–713 (2012)
[4] Pierre Berini, Proc. SPIE 8771, Metamaterials VIII, 87710O (May 6, 2013); doi:10.1117/12.2018441
[5] Vikas Kumar, Heming Wang, Organic Electronics 14 (2013) 560–568
[6]. Manuel Decker, et.al. Advanced Optical Materials 3, 813-820 (2015)
[7] J. A. Gordon, et.al, IEEE Trans. Antennas Wireless Propag. Lett. 8, 1127 (2009)
