2024/02/03 by Zheng-Xiao Cao, Tingting Liu, Cao, Zheng-Xiao +8
Engineering · Physics and Astronomy · #FOS: Physical sciences #Optical Polarization and Ellipsometry #Optics (physics.optics) #Random lasers and scattering media
paper · pdf · doi:10.48550/arxiv.2402.02153
openalex publication_date 2024/02/03 · openalex created_date 2024/02/07 · openalex updated_date 2026/07/28
Astigmatic unitary transformations allow for the adiabatic connections of all feasible states of paraxial Gaussian beams on the same modal sphere, i.e., Hermite-Laguerre-Gaussian (HLG) modes. Here, we present a comprehensive investigation into the unitary modal evolution of complex structured Gaussian beams, comprised by HLG modes from disparate modal spheres, via astigmatic transformation. The non-synchronized higher-order geometric phases in cyclic transformations originates a Talbot-effect-like modal evolution in the superposition state of these HLG modes, resulting in pattern variations and revivals in transformations with specific geodesic loops. Using Ince-Gaussian modes as an illustrative example, we systematically analyze and experimentally corroborate the beamforming mechanism behind the pattern evolution. Our results outline a generic modal conversion theory of structured Gaussian beams via astigmatic unitary transformation, offering a new approach for shaping spatial modal structure. These findings may inspire a wide variety of applications based on structured light.