Optical characterization of melanin.

The optical properties of melanin have been characterized for a number of laser wavelengths in the visible region. The index of refraction of melanin is measured by the conventional method of minimum deviation using a hollow quartz prism at these wavelengths. The inverse adding doubling method based on the diffusion approximation and radiative transport theory have been employed to determine the absorption, scattering, and scattering anisotropy coefficients of melanin from the measurements of diffuse transmission, diffuse reflection and collimated transmission using double integrating spheres. The results obtained by the use of inverse adding doubling method have been compared to the Monte Carlo simulation technique.