Abstract

It is known¹ that the cylindrical glass sample π/2g long with the radial distribution of refractive index works as an objective, where n is the refractive index, n_o is the refractive index at the objective axis, $g=\sqrt{2n_0\Delta n}$ is a constant which characterizes the optical power of the objective, Δn is the refractive index drop between the side surface of the objective and its axis, h_i are aberration coefficients, r is the current radius. One of the most wide-spread methods of creating the racial refractive index distribution is an ion-exchange diffusion². The basis of such technology is the ability of alkali cations of glasses to exchange with the alkali cations of salt melts. The exchange is carried out at temperatures near glass transition ones.

© 1994 Optical Society of America