Optical properties of DNA-polydimethylsiloxane double layered structures

Abstract

To create nanoscale UV sensors and devices based on biomaterials, a detailed study of their optical properties and current transport mechanisms is necessary. In this paper, we study the optical properties of a bilayer structure containing DNA. The transfer matrix method is used. The analysis is performed considering both the real and imaginary parts of the refractive indices of both layers. Reflectance, transmittance, and absorptance spectra are determined. At the average values of the real and imaginary parts of the refractive indices of DNA absorptance passes through a maximum at 215-220 nm and a minimum at 250-260 nm. When considering the spectral distribution of the real and imaginary parts of the DNA refractive index, the absorbance shifts along the wavelength toward longer waves, passes through a minimum at 220 nm, and then through a maximum at 257 nm. The extremes of the absorptance shift to the long-wave region with an increase in the angle of incidence of the radiation. An attempt is made to explain the spectral behaviour of DNA absorptance and its dependence on the value of the imaginary part of DNA refractive index and the angle of incidence of the irradiation. Using the approximation method based on the spectral dependence of acceptance, a formula for the absorption coefficient of DNA is obtained. The acceptability of using the transfer matrix method for studying the optical parameters of organic materials with a complex refractive index is shown.