New class of bioinspired lenses with a gradient refractive index

Abstract

The recognition that eye lenses in nature often employ a gradient refractive index to enhance the focusing power and to correct aberrations has motivated us to construct a synthetic lens using the layered concept encountered in biological lenses. The result is a highly flexible technology for the fabrication of gradient-refractive index lenses that is based on a method of polymer forced assembly. Polymeric nanolayered films with incremental differences in the refractive index are assembled according to a prescribed design and molded into the desired shape. The exceptional flexibility of the process lies in the wide range of lens shapes and index profiles that can be realized. A lens with any refractive index distribution can be achieved within the refractive index range of available coextrudable optical materials.

Polymeric nanolayered gradient refractive index lenses: technology review and introduction of spherical gradient refractive index ball lenses

“…2(a)]. 21,22 These results are plotted as a function of overall PMMA film volume percentage in Fig. 2(b).…”

“…Spherical refractive index contours are created by maintaining the thickness of the curved GRIN preform equal to the difference in the convex and concave mold radii of curvature, as described previously in detail. 22 Curved GRIN preforms can be further transformed into a variety of finished optics by additional diamond turning.…”

“…20 This unique materials approach has enabled the fabrication of GRIN lenses with an unprecedented variety of GRIN profiles, index distribution magnitudes, geometries, and lens apertures. [21][22][23][24][25][26] This paper reviews the enabling technology and describes unique nanolayered polymeric GRIN lenses, including original research demonstrating the fabrication of a polymericlayered GRIN ball lens. These GRIN lenses demonstrate the technology's potential to utilize unrestricted lens geometries and refractive index profiles to improve lens performance, realize optical element savings, and reduce optical system size and weight.…”

Layered lens with a linear dependence of the refractive index change

“…The planar surfaces of gradient lenses make them be very useful for joining with optical fiber and light collimation from a fiber [1,3,4]. Finally, usage of material with gradient change of refractive index in the refractive lenses can be used to allow additional freedom of lens optimization with aim of focusing amplification or aberration corrections [5,6].…”

PLATO: Portable Language-Independent Adaptive Translation from OCR

“…(3) This technique eliminates the prior restrictions by enabling the designer to generate virtually any index of refraction profile in large or small polymer lenses. The fabrication process begins with two polymers of different indices of refraction, which are co-extruded to produce a sheet composed of thin alternating layers.…”