3 rd International conference “Information Technology and Nanotechnology 2017” 43 Spectra and field distribution of photonic-crystal structure with inclusions of metal nanoparticles I.A. Glukhov 1 , S.G. Moiseev 1,2 1 Ulyanovsk State University, 42 Lev Tolstoy Str., 432017, Ulyanovsk, Russia 2 Kotelnikov Institute of Radio Engineering and Electronics of the Russian Academy of Sciences, Ulyanovsk Branch, 48/2 Goncharov Str., 432011 Ulyanovsk, Russia Abstract Transmittance and reflectance spectra as well as field distribution in 1D photonic-crystal structure with embedded dielectric layer and monolayer of metal nanoparticles are characterized. The influence of plasmonic monolayer location on defect modes of photonic-crystal structure is demonstrated with respect to domains of field confinement in the cavity area. Keywords: nanoplasmonics; photonic-crystal structure; defect mode; field localization 1. Introduction In recent years 1D photonic-crystal structures (PCS) created on the basis of different materials are of a special interest to researchers. Owing to periodic modulation of refractive index, photonic spectrum of these structures has a band gap, in which incident radiation is practically totally reflected. This property is critical for practical use as it enables to control optical radiation in data-transmission systems and in laser technology. Particularly remarkable is Fabry-Perot microresonator-like structure composed of two Bragg reflectors with defect layer there between. Defect layer in such-like structure plays the role of optical microcavity (microresonator) on which electromagnetic radiation can be localized. This can add to material-radiation interaction effects. Varying geometrical and physical properties of the structure it is possible to control spectral characteristics of PCS [1, 2] that enables to improve considerably their functionality. For example, through breakdown of the structure periodicity or using materials with controlled properties (non-linear, resonant, magnetogirotropic) photonic spectrum of PCS can be modified considerably. Metallic-dielectric nanocomposite media are advanced materials to be used as microcavity of photonic-crystal resonator. In the field of plasmonic resonance vigorous dispersion of optical properties of these materials is observed [3, 4]. This paper describes the case of ultrathin resonance structure as a monolayer of metal nanoparticles, plasmonic frequency of which coincides with defect mode frequency of PCS. 2. PCS material parameters and transfer matrixes In order to calculate reflectivity and transmission of plane-layered structure with embedded monolayer of nanoparticles we employ T-matrix technique. A special case is interface, optical qualities of which are determined by Fresnel reflection and transmission coefficients [5]. Since array of nanoparticles situated in the same plane interacts with electromagnetic wave like plane interface, it can be also treated as an interface with its own reflection and transmission coefficients. We assume that there are N interfaces in the layered medium, and they are formed by N-1 interfacial boundaries and a single layer of nanoparticles. A space between interfaces is packed by media with different refraction indexes   0... i n i N  . Semi-infinite media are those that have 0 n and N n refraction indexes. Let a harmonic wave is incident on a layered structure in z-direction. To describe its propagation in PCS we introduce the following notation for electric field components inside structure: ( ) i i E z  to the left of i number interface; ( ) i i E z  to the right of i number interface; f E for the propagating forward wave; b E for the propagating backward wave. According to the introduced notation, complex amplitudes of counter-propagating waves on m interface in the layer with reflection index 1 m n  are equal to ( ) f m E z  and ( ) b m E z  . At the same interface but in the layer with reflection index m n they are equal to ( ) f m E z  and ( ) b m E z  . Relationship of these fields on m-interface (to the left and to the right of it) can be expressed as matrix equation: 1, ( ) ( ) = , ( ) ( ) f m f m m m b m b m E z E z I E z E z                  (1) , 1 1, 1, 1, , 1 1, , 1 1, 1 1 = , mm m m m m m mmm m mmm m m r I r t t r r t                 (2)