Wolfgang Sellmeier was a German theoretical physicist who made major contributions to the understanding of the interactions between light and matter.
[2] Before this publication, physicists tried to understand light as a periodic perturbation of an invisible substance that spanned the entire universe: the ether.
[1] The interaction of light with the particles that make up ordinary matter was not yet taken into account when explaining optical phenomena.
This equation is still used today in order to determine the dispersion characteristics of materials, far away from absorption peaks in their spectrum.
[5][6][7] Sellmeier's way of approaching light-matter interaction was swiftly adopted by the physics community and soon formed the basis of theories of dispersion developed by – among others - Hermann von Helmholtz, Woldemar Voigt and Paul Drude.