Characterization of natural and artificial optical activity by the Mueller matrix for oblique incidence, total internal reflection, and Brewster angle

Abstract

Optically active natural or artificial materials are characterized by their optical rotation and circular dichroism. The optical activity of materials is expressed here by the constitutive equations, through a complex chiral parameter. The characteristic equations of optically active materials are the right and left circularly polarized waves with different propagation coefficients. The optical rotation (OR) is associated with differences in the phase velocities, and circular dichroism (CD) is associated with differences in the attenuation constants. These properties can be used to detect and identify biological materials. Artificial materials that are optically active have novel applications. The OR and the CD are usually defined for waves that are normally incident upon chiral materials. At oblique incidence the reflected waves are depolarized. In this manuscript we present numerical simulations to identify pairs of Mueller matrix elements suitable for the measurement of OR and CD for waves obliquely incident upon optically active dissipative media. These simulations can also be used to determine the dependence of the Mueller matrix elements upon the angles of incidence, the permittivity and permeability of the host medium, and the wavelength. For a low-loss host medium, the measurements of OR and CD decouple. Total internal reflection and the Brewster angle are also considered for these optically active materials. These investigations have potential applications in biochemistry, medicine, defense, homeland security, and for the optimum excitation of metamaterial devices.