Measurements of refractive indices and thermo-optical coefficients using a white-light Michelson interferometer

A dispersive white-light Michelson interferometer was used to determine the wavelength dependence of the refractive index (n) in the visible range from 425 to 775 nm and the thermo-optical coefficient (dn/dT) of fused silica (FS) and borosilicate glass (BK7). For FS, the values obtained for n and dn/dT at 546 nm were 1.46079 and 11.3×10−6 K−1, respectively, while the values for BK7 glass were 1.51825 and 2.2×10−6 K−1, respectively, which is in good agreement with the literature. The accuracy of the methodology used for n was almost 10−6, enabling precise spectroscopic characterization of materials across a wide spectral range.