Comparative analysis of key parameters of photonic nanojets from axisymmetric nonspherical microparticles
The effect of “photonic nanojet” (PNJ) arising in the near-field scattering region on the surface of dielectric axisymmetric microparticles (hemisphere, axicon, and combined particles) under optical illumination is theoretically considered. Key PNJ parameters (length, width, and peak intensity) are numerically calculated using the method of discrete-dipole approximation; the dependence of these parameters on the geometric shape of microparticles is analyzed. We show that the use of a special type of combined transparent particles, which consists of an axicon and two attached hemispheres, allows ultra-localized light fluxes with a peak intensity considerably exceeding the corresponding values for particles of simple shapes (hemisphere and axicon).