Tuning the fields focused by a high NA lens using spirally polarized beams (Invited Paper)

Abstract

We show the power of spirally polarized doughnut beams as a tool for tuning the field distribution in the focus of a high numerical aperture (NA) lens. Different and relevant states of polarization as well as field distributions can be created by the simple turning of a λ/2 retardation wave plate placed in the excitation path of a microscope. The realization of such a versatile excitation source can provide an essential tool for nanotechnology investigations and biomedical experiments.