Optical material/lens with big change of refractive index between 980 nm and 1550 nm ?

Hi, Im looking for a material/lens (planar convex) which can focus a beam of 1550 nm and has a high difference of the refractive index for 980 nm and 1550 nm, so that the focol length will be...

26 September 2019 8,857 2 View