{'fraction_non_alphanumeric': 0.020050125313283207, 'fraction_numerical': 0.005012531328320802, 'mean_word_length': 5.440860215053763, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
A fiber-optic autocollimation refractometric method for dispersion measurement of bulk optical materials using a widely tunable fiber Raman laser

A simple and highly sensitive fiber-optic autocollimation method for refractive-index dispersion measurement of solid-state and liquid bulk optical materials is presented. The method is based on the use of a double-pass multimode fiber Raman laser which generates widely tunable emission in a broadband (0.54-1.01 /spl mu/m) continuous spectral range at pumping with the second harmonic of a Q-switched Nd:YAG laser. The optical fiber is used in a specific multifunctional regime where, because of its micrometric core dimensions, it serves simultaneously as a point laser source for the formation of a collimated input emission, as a highly sensitive receiver of the autocollimation backreflectance, and as a medium for nonlinear frequency conversion and generation of a broad-band continuum spectrum. The experimental results obtained in the refractive-index dispersion measurements are fitted to the Sellmeier dispersion equation and used to determine the material dispersion and additional dispersive characteristics of the test optical material.