Abstract

Optical vortices with a ring-shaped spatial form and an orbital angular momentum (OAM) of ℓφ [1], arising from their helical wavefronts characterized by an azimuthal phase, exp(iℓφ) (where ℓ is an integer termed the topological charge), have been widely exploiting a variety of research fields. These include optical trapping and manipulation [2], fluorescent microscopes with a high spatial resolution beyond the diffraction limit [3] and materials processing [4,5]. The aforementioned applications strongly desire wavelength-tunability and OAM-versatility to optical vortex sources [6].

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