Aberration-compensated supercritical lens for sub-diffractive focusing within 20° field of view

The supercritical lens has shown a remarkable capability of achieving far-field sub-diffraction limited focusing through elaborating a modulated interference effect. Benefiting from the relative high energy utilization efficiency and weak sidelobe properties, the supercritical lens holds significant advantage in a series of application scenarios. However, all of the demonstrated supercritical lenses mainly work in the on-axis illumination condition, so the off-axis aberration effect will severely deteriorate its sub-diffraction limit focusing capability for the illuminating beam with an oblique angle. In this work, an aberration-compensated supercritical lens with single-layer configuration is proposed and experimentally demonstrated. Such a single-layer supercritical lens consists of multilevel phase configurations patterned with the two-photon polymerization lithography technique. The simulation and experimental recorded results show that the aberration-compensated supercritical lens with a numerical aperture value of 0.63 could achieve a far-field sub-diffraction limited focusing property within 20° field of view at a wavelength of λ = 633 nm. This monochromatic aberration-compensated supercritical lens with single-layer configuration indicates excellent potential in the development of laser scanning ultrahigh optical storage and label free super-resolution imaging.