Light-field camera based on a hexagonal array of nanostructured GRIN microlenses

We present a compact light-field camera built using a flat-surface gradient index (GRIN) microlenses array. First, we report on the design, fabrication and characterization of a hexagonal array of nanostructured GRIN microlenses suitable to build the camera. The concept of a nanostructured GRIN microlens is based on the effective medium theory. The nanostructured GRIN lens is composed of several hundred subwavelength rods made with the use of the stack-and draw technique, which was originally devised for fabrication of photonic crystal fibers [1]. A single GRIN microlens is fabricated from two different glasses, one with low and one with high refractive index value [2]. To develop a hexagonal array of nanostructured GRIN lenses we apply a modified stack-and-draw technique as a second step. The finally-formed element is made of 469 GRIN micro lenses, each 20 μm in the diameter, and is characterized by 100% fill factor. The flat-surface element is easy to integrate with other optical components.