Dispersion Engineering for Multifunctional Photonic Crystal Based Nanophotonic Devices at Infrared Wavelengths

TIn this paper, we report the design, the fabrication and the near field optical microscopy of Negative Index Material (NIM) and GRadient INdex (GRIN) photonic crystal based flat lenses. They were fabricated on the basis of an InPbased photonic crystal technological platform including hole and pillar networks fabrication at nanometer scale. They show the possibility of sub-wavelength focusing by all dielectric periodic or quasi-periodic crystals. Particular attention is paid to the analysis of SNOM images using three-dimensional simulations. Finally, in order to demonstrate the versatility of our approach, a two-dimensional cloaking device mixing hole and pillar arrays is evaluated to pave the way for future integrated nanophotonic devices with complex functionalities. OCIS codes: 220.2740, 230.5298, 080.2710, 170.6960 First, an optimized PC-based flat lens optimized in resolution (~0.8λ) and transmission efficiency (~30%) is presented. It operates in the negative refraction regime (n = -1) [10-12] with a patterning scale (a/λ) of 0.3 (a denotes the crystal period). The double focusing of a quasi-point source was unambiguously experimentally assessed and validated by three dimensional (3D) simulations. Second, the focusing of a plane wave was studied by means of so-called GRIN (gradient index) lenses [13-19]. Square lattices of hole and pillar arrays were designed, operating for complementary optical field polarization, in the long wavelength regime (a/λ < 0.1). Index variation in the direction transverse to the direction of propagation is obtained by varying the hole or pillar diameters while the lattice period is kept constant. Here again, the focusing is clearly evidenced by means of SNOM measurements. Then, in a prospective manner, partial invisibility [20,21] was searched by means of two dimensional (2D) transformation optics concepts to go beyond initial proposals based on mixed passand stopband photonic crystals [22]. Here, the idea consists in decreasing the scattering by an object deposited on a reflector [23,24]. A preliminary feasibility study of such a device will be initiated. The plan of the paper is as follows: Section II is devoted to fundamental physical principles which allow us to exploit ultrarefraction phenomena using local and bulk dispersion engineering in patterned dielectrics. In section III, the InP-based technological Citation: Hofman M, Scherrer G, Kadic M, Mélique X, Śmigaj W, et al. (2013) Dispersion Engineering for Multifunctional Photonic Crystal Based Nanophotonic Devices at Infrared Wavelengths. J Nanomed Nanotechnol 4: 185. doi:10.4172/2157-7439.1000185