Generation of grafted perfect vortex beams by Bessel phase cross-splicing and parallel detection

A grafted perfect vortex beam generation method based on the Bessel phase is proposed. Leveraging the conjugate property of the Fourier transform, the grafted Bessel phase is obtained by cross-splicing the diagonal regions of Bessel phases with distinct topological charges. This phase grafting approach effectively suppresses interference arising from distinct topological charges, and the radial distribution of the grafted phase conforms precisely to a Bessel function. Numerical simulation yields a nearly perfect vortex beam. In the photoelectric experiment, the grafted Bessel phase is loaded onto the spatial light modulator, and the grafted perfect vortex beam containing multiple topological charges is successfully generated after passing through a Fourier lens. A mode parallel detection method for grafted perfect vortex beams is proposed based on a vortex array with tilted phases. A Bessel–Gaussian vortex array containing distinct topological charges with their tilted phases is constructed. In the diffraction field, the Gaussian points demodulated by distinct topological charges are spatially separated rather than superimposed at the center of the frequency domain. By loading the hologram of the Bessel–Gaussian vortex array onto the spatial light modulator and identifying the Gaussian points at distinct positions in the diffracted light field, the parallel detection of the grafted perfect vortex beam mode is achieved. The proposed method is expected to enhance the encoding capacity and provide a promising technical pathway for high-dimensional optical communications, spatial multiplexing, and complex optical field manipulation.