Figure 2

(a) Hologram pattern from the fork grating with \(b_{\mathrm{H}}\) = 1 and \(b_{\mathrm{V}}\) = 1. The inset shows a schematic of the fork grating. (b) \(A(\rho _{fn}, \phi _{fn})\) (first row) and phase distribution (second row) of the vortex diffraction waves for \(nb^{\prime } = n_{\mathrm{H}} b_{\mathrm{H}} +n_{\mathrm{V}} b_{\mathrm{V}} =\) 0, \(\pm 1\), \(+2\). Images in the third row present simulated phase patterns for these vortex diffraction waves. (c,d) TC spectrum for each diffraction wave.