Diffraction-limited flat reflective microlenses by plasmonic photopatterning of molecular orientations

In this study, we demonstrate that flat reflective microlenses with different f -numbers and focal lengths can be designed by manipulating the Pancharatnam–Berry (PB) phase obtained by light upon reflection from cholesteric liquid crystals and fabricated with high quality using a plasmonic photopatterning technique. We have measured the point-spread functions of these microlenses and show that they are diffraction-limited. An advantage of this approach for fabricating flat micro-optical devices is that it allows for the simultaneous design of diffraction-limited quality and low fabrication cost.