Modeling and Constituent Design of SPR Based and/or Waveguide Type Sensors

Abstract

This work is motivated by interest to the waveguide geometry which is attractive because it allows the surface polariton (SP) sensors to be incorporated into the integrated optical system. Inclusion of additional covering and/or (intermediate) dielectric (SiO x ; x=2) and/or conducting (ITO) (tuning) layers in geometry with diffraction grating (DG) as input -coupling component to excite SPs is useful in modifying the SP resonant (SPR) characteristics and creating the potential for universal devices with multifunctional sensing capability (optochemical sensors [1], polarization -and wavelength (angle) -selective photodetectors etc.[2]). Properties (reflectance/ transmittance) of a multilayer stack with DG as optical waveguide (or a leaky quasi-waveguide) are described. Particularly emphasis is placed on modeling the spectral (angular) resonance characteristics of the device modified by inclusion of a heavily doped oxide (ITO) layer. The adequate optical model approaches for the dispersion of the optical constants of ITO films were proposed to full description of the photoresponse and to optimization of future device design. In this paper the possibility of implementing the SPR sensing principle in optical (quasi)waveguide structures designed was demonstrated. We explored constituent design considerations to show how variation structural parameters affect SPR based sensor (detector) response.