Researchers from the DON team have demonstrated and analyzed the generation of high-purity second-harmonic vortices with dielectric metasurfaces. These results are published in Light: Science and Applications.
Vortex beams are currently drawing a great deal of interest, from fundamental research to several promising applications. While their generation in bulky optical devices limits their use in integrated complex systems, metasurfaces have recently proven successful in creating optical vortices, especially in the linear regime. In the nonlinear domain, of strategic importance for the future of classical and quantum information, to date orbital angular momentum has only been created in qualitative ways, without discussing discrepancies between design and experimental results. Here, we demonstrate and analyze the generation of high-purity second harmonic (SH) optical vortices via dielectric meta-holograms. Through full-wave simulations and a proper fabrication protocol, we achieve efficient frequency doubling of an unstructured pump beam into SH vortices with topological charges from 1 to 10. Interferometric and modal-purity measurements confirm the generation of high-quality SH vortices with minimal deviations from the intended design thanks to a quasi-local control over the SH phase. Through systematic comparisons between experimental data and semi-analytical calculations, we also provide a clear insight into the occurrence of ghost vortices in the metasurface-generated harmonic beams, highlighting the importance of simple designs that can be readily transposed into fabricated devices with high fidelity. These findings underscore the potential of nonlinear dielectric metasurfaces for versatile structured-light generation and manipulation, paving the way for future developments in integrated photonic systems
Reference :
Unravelling the nonlinear generation of designer vortices with dielectric metasurfaces
L. Coudrat, G. Boulliard, J.M. Gérard, A. Lemaître, A. Degiron, G. Leo
À lire aussi
On-Chip Ferromagnetic Resonance for van der Waals Heterostructures: Anisotropy and Damping of Cobalt Interfaced with Exfoliated 2D Materials
A collaboration between the technical hub, the clean room platform and the TELEM group at MPQ laboratory has developped a new experiment demonstrating that standard broadband ferromagnetic resonance can still be effective to probe the magnetization dynamics of “thin...
Materials science – When the surface reaches deep inside…
Crystalline surfaces often exhibit reconstructions, usually assumed to affect only a few atomic layers below the surface. A collaborative study (conducted by the Matériaux et Phénomènes Quantiqueslaboratory in Paris, the Institut P’ in Poitiers, and the SixS beamline...
Exhibition – Matériaux et phénomènes illustrés
General public exhibition, free access. At the MPQ laboratory, electronic and photonic chips are designed and manufactured for use in both fundamental research and industrial applications, such as quantum telecommunications and high-precision mechanical sensors.The...
Emergent Equilibrium in All-Optical Single Quantum-Trajectory Ising Machines
A collaboration between the Theory group at MPQ, CREF Rome, and Sapienza University of Rome has shown that multimode all-optical systems driven by two-photon processes can reach thermal equilibrium at the level of single quantum trajectories. The study is published in...