Theoretical basis of optical engineering of ultrathin crystalline film-structures

Abstract

Based on microscopic (exciton) theory of optical properties of perturbed ultrathin molecular films, the absorption, reflection, and transparency indices were formulated and presented in dependence on frequencies of an external electromagnetic field in near IR region. It has been shown that all optical properties depend on the position of the crystal plane with regard to boundary planes of the film. We have determined and analyzed optical properties relations for the whole film structure based on the consideration for multiple reflection, absorption, and transparency in observed multilayered structure. The four-layered dielectric nanofilms with different boundary conditions on surfaces were analyzed and some discrete resonant absorption lines were obtained. Their number, position, and distribution depend on the boundary parameter values, i.e. on the type and the technological process of their preparation/fabrication. Practically monochromatic absorption may occur. Unlike the corresponding bulk-samples, which are total absorbers throughout the near IR, region, in ultrathin films will appear selective and discrete reflection and transparency. These results could provide a great contribution to optical engineering of nanostructures, especially in technology of designing of new electronic and photonic equipment, and for nanoparticles construction for drug carrier/delivery in nanomedicine.