Focusing of laser light using a dielectric cylinder carrying higher-order whispering gallery modes

We demonstrated that plane wave diffraction on a dielectric cylinder with resonant radius produces a broader focal spot in case of TM-polarization, and resonant radiuses of whispering gallery modes (WGM) for TM-polarized illumination are significantly greater than corresponding radiuses for TE-polarization. We also showed that high order WGM are exited in cylinders with radiuses close to extreme value conditions of Bessel functions, and that increasing WGM order not necessary leads to stronger light confinement in the focal spot.