Biologically Inspired Optical Systems - Biomimetics: Biologically Inspired Technologies - page 295

(a) (b)
Figure 11.4 (a) Spherical aberration from a spherical lens with homogenous index of refraction; (b) properly
focused rays from a spherical lens with a refractive index gradient.
(b) (c)
Figure 11.5 (a) Schematic, (b) curved retinal structure, (c) close-up of S-flexural joints. (From Hung, P.J., Jeong,
K., Liu, G.L., and Lee, L.P. Applied Physical Letters 2004: 85(24), 6051-6053. With permission.)