Generation of nonlinear Airy beams with switchable acceleration direction

Abstract

Airy beams, which propagate along a curved trajectory, have been widely utilized in optical tweezers, biomedical analysis, and material processing. However, the dynamic regulation of nonlinear Airy beams is still challenging. Here, we demonstrate directionally switchable nonlinear Airy beams via three-dimensional (3D) nonlinear photonic crystals (NPCs) fabricated by the femtosecond laser erasing technique. The 3D NPCs contain several sequential arrays of spatially modulated nonlinearities with different spatial frequencies and cubic coefficients. By tuning the wavelength of the fundamental beam, the quasi-phase-matching condition can be switched to modulate the acceleration direction and wavelength of the generated nonlinear Airy beam. This offers a versatile platform for dynamic nonlinear Airy beam generation, paving the way for applications in optical trapping, optical communication, and biomedical imaging.