Optical properties of layers of symmetric molecular nanofilms

摘要

The changes of optical properties under boundary presence in molecular crystal nanofilm were theoretically investigated in this work. The dispersion law and states of excitons as well as their space distribution along boundary direction have been determined using adjusted Green's function method and also by combined analytical and numerical calculations. We study the basic micro and macroscopic physical characteristics of symmetric ultrathin molecular crystalline films and one can see that essential optical properties of these systems arise with perturbation conditions, which appear at their surface layers. On the basis of real and imaginary part of relative permittivity, the absorption, refraction, reflection and transparency indices were determined, and the influences of boundary parameters on occurrence of a very selective and strictly discrete absorption, refraction and transparency were analyzed. What we have found particularly interesting is the significant percentage of reflected and transparent electromagnetic IR radiation in the nanofilm, although bulk samples of the same crystallographic structure are complete absorbers of this spectrum.