"Just over two years ago, PhD student at Swinburne’s Centre for Micro-Photonics, Xiaorui Zheng, tried fashioning a lens using graphene oxide — a variation of the super-strong, atom-thick carbon material, graphene. The team, led by Associate Professor Baohua Jia, developed a three-dimensional printer that could quickly and cheaply produce the lens using a sprayable graphene oxide solution. Lasers were used to precisely pattern the surface, creating three concentric rings of reduced graphene oxide, which enabled its extraordinary focus"

No I think it's purely geometrical.