Fig. 5: Experimental demonstration of achromatic non-diffracting perfect vortex beam (ANPVB). | Nature Communications

Fig. 5: Experimental demonstration of achromatic non-diffracting perfect vortex beam (ANPVB).

From: Ultrabroadband, achromatic, and non-diffracting perfect optical vortex generation via radial momentum control in dielectric metasurfaces

Fig. 5: Experimental demonstration of achromatic non-diffracting perfect vortex beam (ANPVB).

a1, b1, c1 The overall scanning electron microscopy (SEM) images of the fabricated metasurfaces generating ANPVBs with parameters (α = 18, β = 0.8, γ = 3, t = 700, δ = 1, R = 0.54 mm, l = 1, 15 and 30). The local SEM images (a2, b2, c2) (top view) and (a3, b3, c3) (side view), respectively. d–g Captured intensity distributions at z = 3, 6, 9, 12, 15, 18, 21, 24, 27 and 30 mm of these three types of ANPVBs under circularly polarized incident light at the wavelengths of 450, 532, 633 and 780 nm, respectively. Corresponding captured interference intensity distributions on the far right at z = 18 mm under linearly polarized incident light. h Plot of the corresponding diameters with respect to axial positions. The scale bars in (a1–c1), (a2–c2), (a3–c3) and (d) represent 200 μm, 1 μm, 1 μm and 100 μm, respectively.

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