Fabrication of a close-packed hemispherical submicron lens array and its application in photolithography

The fabrication and characteristics of close-packed lens arrays with a feature size close to the optical diffraction limit are presented in this study. By controlling the size of the submicron nickel rods and the time for reactive dry etching, the hemispherical lens array with a submicron period is made directly on a borosilicate glass. Finite-difference time-domain calculations and optical near-field measurements show that such a lens array can generate a subwavelength optical spot array near the glass surface. Moreover, the spot array periodically appears in the propagation direction. Using this novel optical property, we propose a photolithographic method for the mass-production of multilayer hexagonal structures with a period of 500nm.