Does this mean it has an index of refraction that depends on wavelength? How can that be? Is the bond length some multiple of blue (or green/red), where there's some quick "change" in what the photon "sees"?
0. https://en.wikipedia.org/wiki/Kramers%E2%80%93Kronig_relatio...
> The refractive index may vary with wavelength. This causes white light to split into constituent colors when refracted. This is called dispersion. This effect can be observed in prisms and rainbows, and as chromatic aberration in lenses.
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> For most materials the refractive index changes with wavelength by several percent across the visible spectrum. Nevertheless, refractive indices for materials are commonly reported using a single value for n, typically measured at 633 nm.
So we were all lied to in our introductory optics classes. n isn't a constant for a given material but rather n(lambda) but weakly.
All the physical explanations I've seen invoke the EM equations and quantum mechanics to explain it (and I don't understand it well enough to translate).