High resolution Shack-Hartmann sensor based on array of nanostructured GRIN lenses

Kasztelanic R., Filipkowski A., Pysz D., Stepien R., Waddie A.J., Taghizadeh M.R., and Buczynski R.

Optics Express

25 (3), 2017, 1680-1691, 10.1364/OE.25.001680

We present a novel method for the development of a micro lenslets hexagonal array. We use gradient index (GRIN) micro lenses where the variation of the refraction index is achieved with a structure of nanorods made of 2 types of glasses. To develop the GRIN micro lens array, we used a modified stack-and-draw technology which was originally applied for the fabrication of photonic crystal fibers. This approach results in a completely flat element that is easy to integrate with other optical components and can be effectively used in high refractive index medium as liquids. As a proof-of-concept of the method we present a hexagonal array of 469 GRIN micro lenses with a diameter of 20 μm each and 100% fill factor. The GRIN lens array is further used to build a Shack-Hartmann detector for measuring wavefront distortion. A 50 lens/mm sampling density is achieved.