Collimating three-axicon zoom system for interferometric Bessel beam side lobe cancellation

Abstract

Optical Bessel beams are used in numerous applications like fluorescence microscopy, material processing and optical trapping. These applications require Bessel beams having a central core with defined full width at half maximum and a defined axial length. Often, the side lobes of Bessel beams, which are associated with their non-diffracting properties, can interfere with the experimental process. We theoretically describe and practically verify the performance of a new refractive optical system to generate zoomable annular ring intensities. The ability to zoom the output ring diameter allows for flexibly choosing the Bessel beam parameters. Secondly, we introduce the use of a Michelson interferometer for destructively interfering Bessel beam side lobes in one direction. If two Bessel beams of zeroth order and first kind are coherently superposed with a small shift with respect to each other, their side lobes are enhanced in one direction and cancelled in the other direction. We suggest that applications like light-sheet microscopy can exploit the axis of destructive interference to improve their contrast.