Diseño y construcción de un esparcímetro de luz

Abstract

In this paper, we present the design and construction of a light scatterometer optimized to carry out measurements of high angular precision and weak signals, to study random rough surface of thin films. The scatterometer has the advantages of great ease of alignment and high angular precision as compared with commercial one. To prove the equipment angular precision, we report experimental results of reflection measurements using the technique of attenuated total reflection (ATR) in the Kretschmann configuration of two systems which were excited electromagnetic modes. The first system used is BK7 glass-prism/Ag/air and the second is BK7 glass-prism/MgF$_{2}$/ZnS/MgF$_{2}$/air. With this apparatus, reflection minima could be measured which in the 50% of it's depth have a width of 0.1$^{\circ }$. As detection sensibility test of the equipment, we report scattering measurements carry out to the second system. Fitting the experimental results, a good coincidence between theory and experiment was found. We report values of thickness, refractive index, absorption index, height of the roughness and correlation length obtained from the fitting. These values were compared with those reported in the literature.