Problem 5.184

A quartz wedge with refracting angle \(\Theta=3.5^{\circ}\) is inserted between two crossed Polaroids. The optical axis of the wedge is parallel to its edge and forms an angle of \(45^{\circ}\) with the principal directions of the Polaroids. On transmission of light with wavelength \(\lambda=550\) nm through this system, an interference fringe pattern is formed. The width of each fringe is \(\Delta x=1.0 \mathrm{~mm}\). Find the difference of refractive indices of quartz for ordinary and extraordinary rays at the wavelength indicated above.