A new gradient-index lens with high numerical aperture has been fabricated by a new ion-exchange technique. In this treatment, a glass rod doped with a highly polarizable ion (dopant A) is immersed into KNO3 salt doped with a medium polarizability ion (dopant B). Dopant B penetrates into the rod and modifies the refractive-index profile of the lens. This new lens has 0.6 N.A. and gives a 1.18-µm spot diam in the light-focusing system. This lens gives good results also in a light source coupling system and is useful in microoptic devices.
© 1983 Optical Society of America
T. Yamagishi, K. Fujii, and I. Kitano, "Gradient-index rod lens with high N.A.," Appl. Opt. 22, 400-403 (1983)