2025/07/01 by Xuening Wang, Wang, Xuening, Yuxin Guo +13
Physics and Astronomy · #FOS: Physical sciences #Nonlinear Photonic Systems #Optics (physics.optics) #Pattern Formation and Solitons (nlin.PS) #Photonic Crystals and Applications #Photorefractive and Nonlinear Optics
paper · pdf · doi:10.48550/arxiv.2507.00818
openalex publication_date 2025/07/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report stable composite vortex solitons in the model of a three-dimensional photonic crystal with the third-harmonic (TH) generation provided by the quasi-phase-matched quadratic nonlinearity. The photonic crystal is designed with a checkerboard structure in the ( x,% y) plane, while the second-order nonlinear susceptibility, d(z), is modulated along the propagation direction as a chains of rectangles with two different periods. This structure can be fabricated by means of available technologies. The composite vortex solitons are built of fundamental-frequency (FF), second-harmonic (SH), and TH components, exhibiting spatial patterns which correspond to vortex with topological charges s=1, a quadrupole with s=2, and an anti-vortex structure with s = -1, respectively. The soliton profiles feature rhombic or square patterns, corresponding to phase-matching conditions φ=0 or π, respectively, the rhombic solitons possessing a broader stability region. From the perspective of the experimental feasibility, we show that both the rhombic and square-shaped composite vortex solitons may readily propagate in the photonic crystals over distances up to ∼ 1 m. The TH component of the soliton with s=∓ 1 is produced by the cascaded nonlinear interactions, starting from the FF vortex component with s=± 1 and proceeding through the quadrupole SH one with s=2. These findings offer a novel approach for the creation and control of stable vortex solitons in nonlinear optics.