The perfect optical vortex (POV), the ring size being independent of its topological charge, has found potential applications in optical tweezers and optical communications. In this Letter, Ming Lei’s research team reported a new kind of POV, termed as double-ring POV (DR-POV), whose diameters of the two rings are independent of topological charge. They theoretically demonstrate that such a vortex is the Fourier transform of an azimuthally polarized Bessel beam. Experimental results agree well with theoretical prediction. They further investigated the vortex nature of the DR-POV through an interferometric method, showing that the two rings of the vortex have the same topological charge value (magnitude and sign). The specular properties of the DR-POV may find application in optical tweezers, such as trapping and rotating of low-refractive-index particles in the dark region between the two rings.

（Original research article "Neurocomputing Vol. 44, Issue 6, pp. 1504-1507 (2019) https://www.osapublishing.org/ol/abstract.cfm?uri=ol-44-6-1504"）