Super-Oscillation Far-Field Focusing Lens Based on Ultra-Thin Width-Varied Metallic Slit Array

摘要

A super-oscillation far-field focusing micro-lens based on continuous amplitude modulation is experimentally demonstrated with 40-nm thick width-varied sub-wavelength metallic slit array. The micro-lens is designed and fabricated with numerical aperture 0.976 and focal length for wavelength nm. Experimental results show that the focal length is , and the focal line full width at half maximum is , which is smaller than the corresponding diffraction limit and the super-oscillation criterion . A great suppression of sidelobes was observed in the measured focal plane area, and the largest sidelobe intensity was found only 10.6% of the central lobe intensity, leading to a wide field of view.