Grin Glasses

Abstract

One of the bulk glasses on which the sol-gel technique is applied with a potential advantage over other technique is r-GRIN material having a nearly parabolic refractive index profile which varies from the center towards the periphery of a rod with a gradient expressed by the following equation;

$$ {n^2}(r) = n_0^2[1 - {(gr)^2} + {h_4}{(gr)^4} - {h_6}{(gr)^6} + - - - ] $$

((1))

where n₀ is the refractive index at the center axis, r is the radial distance from the rod center axis, g is a focusing constant determining the power of the lens, and h₄ (=2/3) and h₆ (=17/45) are higher order dimension less parameters.