Nonlinear ellipse rotation measurements in optical thick samples

• DOI: 10.1007/s00340-015-6178-x
• Publication Date: 2015-07-29T10:02:12Z
• Authors: M. L. Miguez; E. C. Barbano; J. A. Coura; S. C. Zílio; L. Misoguti
• Keywords: 0103 physical sciences; 01 natural sciences

Nonlinear refractive indices of several optical glasses were measured by means of the nonlinear ellipse rotation method in a tightly focused laser beam condition, leading to the improvement of the spatial resolution which allows probing the local refractive nonlinearity with better accuracy. The use of a short focal length results in a Rayleigh range shorter than the sample thickness, and this feature can be explored to measure two stacked samples in a single run. In this way, it is possible to simultaneously probe a reference and an unknown sample, improving significantly the refractive nonlinearity determination. Several optical glasses were characterized by this method using fused silica as reference.