Light scattering from chiral polymers

The reflection from a semi-infinite chiral medium is analyzed rigourously b y obtaining the Fresnel coefficients of reflection as well as the depolariz ation coefficients for the case of illumination by a plane wave with linear polarization. The chiral material is described electromagnetically by the constitutive relations D = epsilon(0)<(epsilon)over cap>E + i xi(c)B and H = i xi(c)E + (1/mu mu(0))B, where epsilon(ij) = epsilon(perpendicular to)(d elta(ij) - n(i)n(j)) + epsilon(II)n(i)n(j) is the dielectric tensor of the chiral substrate (z less than or equal to 0), n is the normal vector to the half-space, mu is the magnetic permeability, epsilon(0) and mu(0) are Vacu um permittivity and permeability, xi(c)[Omega(-1)] is the chiral component of the polymer admittance. The constants epsilon(perpendicular to)(omega), epsilon(II)(omega), xi(c)(omega), mu(omega) are supposed to be complex and to have values that are determined by usual ellipsometric measurements. For small values of the dimensionless chirality parameter \g(c)\ = root(mu(0)/ epsilon(0))\xi(c)\ and by supposing epsilon(perpendicular to) = epsilon(II) = epsilon = epsilon(1) + i epsilon(2), mu = 1 (the isotropic nonmagnetic c ase) and appropriate perturbation theory is developed Ellipsometric charact erization (and its interpretation) for the polymer sample P7MB (poli-bi-ben zoate with spacers containing 7 ethylene units) is given.