Fig. 3: Micro vortex beam emitters based on VCSELs.

a Schematic of the VCSEL with an integrated spiral phase plate on the emitting surface for direct OAM beam generation¹⁰⁸. b Schematic illustration of the VCSEL with integrated metasurface to create complex vectorial fields with well-defined wavefronts, the inset shows the employed meta-atom with rectangular cross-section¹¹⁴. c Top row: schematic illustration of the VCSEL with an integrated non-contact spiral phase plate fabricated by fs laser 3D printing¹¹⁵. Bottom row: Scanning electron microscope (SEM) image of a fabricated VCSEL integrated with two-layer cascaded SPPs for generating vortex beam with l = 15. d Addressable and scalable 1 × 5 vortex micro laser array with specific topological charge in each channel¹¹⁵. Figure a from ref. ¹⁰⁸. with permission from the Optica Publishing Group. Figure b is reprinted from ref. ¹¹⁴. with permission from the John Wiley and Sons. Figures c and d are adapted from ref. ¹¹⁵. with permission from the American Chemical Society