In the standard <i>M</i>-line method for the characterization of graded-index films, an analytical curve is fitted to the waveguide mode measurements and extrapolated to provide the refractive index in the zero-depth limit. Here we review our polarimetric approach to a direct near-surface measurement, which complements the <i>M</i>-line method. Also, we present its new and more straightforward version, which is applicable to existing samples and does not require masking before ion exchange.
© 2003 Optical Society of America
Marcelo B. Pereira and Flavio Horowitz, "Simple Polarimetric Approach to Direct Measurement of the Near-Surface Refractive Index in Graded-Index Films," Appl. Opt. 42, 3268-3270 (2003)