Femtosecond-laser written gradient-index Fresnel lenses for vision correction

摘要

Our group reported the creation of gradient-index (GRIN) microlenses (150 um diameter) in hydrogels through the use of femtosecond laser induced refractive index change (LIRIC) (1). In this study, we report the optical quality of large area stitched Fresnel lenses (6mm diameter, 543nm design wavelength). Five spherical lenses (Range: a??3.0 to +1.5 D) and one cylindrical lens (a??1.5 D) were created. Each lens was produced in a single layer within a plano hydrogel using a 400nm frequency doubled Ti:sapphire laser and a galvo-scanning system (field of view: 245??88 um). The resulting change in wavefront aberrations was assessed with a Shack-Hartmann wavefront sensor (5.8mm pupil, 543nm wavelength). The measured writing error was 0.11 ?± 0.07 D of the desired target (defocus or astigmatism). Induced HORMS was 0.14 ?± 0.03 um. Future work includes visual performance testing. This work shows the potential of femtosecond writing for the creation of accurate phase structures exhibiting high visual quality with LIRIC.