Talbot-Rayleigh interferometer

In the Talbot-Rayleigh interferometer developed by Warenghem et al. [55, 56], the planar-oriented nematic cell is inserted in the focal plane of an ordinary spectroscope that covers only half of the field of polychromatic light. In this way dark bands (Talbot bands) appear due to the interference between the upper and the lower part of the beam. The position of the bands is correlated with the phase retardation (and, therefore, with the refractive index) induced by the nematic layer. By means of a proper spectrum analysis, dispersion curves of n and can also be determined. 

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