Spectrally resolved white light interferometer for measuring dispersion in the visible and near infrared range
arXiv:2401.17335 · doi:10.1016/j.measurement.2018.03.012
Abstract
We design a spectrally resolved interferometer to measure the refractive index of transparent samples over a broad spectral range between 400 and 550 nm. The measuring device consists of a Michelson interferometer whose output is analysed by means of three fibre spectrometers: a homemade prism spectrometer which obtains the interferogram generated by the sample between 400 and 1050 nm, a homemade transmission grating spectrometer that measures the interferogram in between 950 and 1550 nm, and a commercial Czerny Turner spectrometer used to make high precision measurements of the displacement between the Michelson mirrors. The whole system is illuminated by a white light source with an emission spectrum similar to that of a black body. We test the instrument on solid and liquid samples achieving accuracy of up to 0.0001 in the refractive index after fitting it with the Cauchy formula.
18 pages, 11 figures, 3 tables