Novel method for optical characterization of films

摘要

Nondestructive three dimensional refractive index measurements are used for the determination of both crystallinity and orientation in thin polymer films. The prism wave-guide coupler is particularly suited for three dimensional isotropic and anisotropic thin film studies because of the quantitative character of the information obtained and the ease of data acquisition. It has been limited, however, to measuring the refractive index of transparent or weakly absorbing films. The present study shows that by using a modified prism waveguide coupler it is possible to determine the complex refractive index over a range from transparent to highly absorbing films from the internally reflected light intensity. Thus both the refractive index, n, and the extinction coefficient, k, can be obtained.