High-efficiency elliptical perfect vortex beam generation based on 3D nanoprinted spiral ellipse-type lens

Traditional perfect vortex beams exhibit symmetric annular intensity distribution and a limited number of adjustable degrees of freedom, which restrict their applicability in optics. Herein, a spiral ellipse-type lens (SEL) fabricated via two-photon polymerization 3D nanoprinting is proposed for the generation of elliptical perfect vortex beams (EPVBs). The perfect characteristics of the EPVBs are verified by numerical simulations and experiments. Experimental results indicate that the prepared SELs have an average generation efficiency of 69.3%. Analyses of the light field evolution demonstrate the formation of a Hermite-Laguerre-Gaussian (HLG)-like beam with nodal lines associated with the topological charge following the EPVBs. Interferometric measurements were carried out to confirm the correctness of the topological charge. Further orbital angular momentum (OAM) spectrum analysis revealed the mode composition and mean OAM per photon of the generated EPVBs. Moreover, a multi-EPVB encoding and decoding scheme is presented, showcasing the potential of SELs in high-capacity information storage and encryption. We envision that the proposed SELs will further broaden the application scenarios of perfect optical vortices.