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.

Manipulation of the overall polarization orientation in the focal volume of high numerical objectives

“…The far-field focusing investigation by a high numerical objective (OB) has long been an attractive topic [1][2][3][4][5][6][7][8][9][10] . The tightly focused subwavelength spot, an either transversely [1] or axially super resolved spot [7] , or a specially shaped focal spot, such as a doughnut-like spot [4,11] , a long-needle-like spot [9,12] , or a complete spiral spot [10] , can always find potential applications in various fields, such as high-resolution optical microscopic fluorescence imaging [12,13] , optical trapping and manipulation [14][15][16] , optical data storage [17] , optical lithography [18] , plasmonic wave excitation [19] , and metamaterial fabrication [20] . Most of the applications are polarization-sensitive.…”