Figure 8
From: Planar binary-phase lens for super-oscillatory optical hollow needles
Comparison between COMSOL numerical simulation and experimental results, where the optical intensity, sidelobe ratio, and FWHM are given in arbitrary unit, ratio value, and λ respectively. (a) simulation and (b) experimental results of the 2-dimentional optical intensity distribution in the XZ propagation plane; (c) the normalized central ring peak intensity, (d) the sidelobe ratio, and (e) the transverse average FWHM distributions along the propagation direction. The black arrow indicated the 10-λ longitudinal FWHM of the experimentally obtained hollow needle. The black and wine-colored dashed-dotted lines indicate the diffraction limit (i.e., 0.5λ/NA) and super-oscillatory criterion (i.e., 0.38λ/NA), respectively.
