I was kind of hoping they would explain why it helps prevent chromatic aberration. Unfortunately their explanation stops short, basically just saying that 'it does' without going into the details of why.
My first guess would be something to do with it having a well suited refractive index, but it is almost equal to that of glass. The best candidate I've found is that the group velocity dispersions are opposite, which seems like it might explain it, if only I knew what it meant.
My first guess would be something to do with it having a well suited refractive index, but it is almost equal to that of glass. The best candidate I've found is that the group velocity dispersions are opposite, which seems like it might explain it, if only I knew what it meant.