White-light interferometry with the equalization wavelength determination used to measure group velocity dispersion in optical samples

摘要

A new white-light spectral-domain interferometric technique is used to measure the group velocity dispersion (GVD) in optical samples of known thicknesses. In the experimental setup comprising a halogen lamp, a Michelson interferometer with an optical sample, and a low-resolution spectrometer, the equalization wavelength as a function of the displacement of the interferometer mirror is measured by the spectrometer. From the measured equalization wavelengths either the differential group refractive index of the optical sample as a function of the equalization wavelength or the difference of the mirror displacements at two different equalization wavelengths is obtained to determine the GVD in the optical sample. The new white-light spectral-domain interferometric technique is applied to measure the GVD in two fused-silica optical samples of known thicknesses. In a broad spectral range it is confirmed that the GVD in both samples agrees well with the GVD resulting from the Sellmeier dispersion equation.