High-angle deflection of metagrating-integrated laser emission for high-contrast microscopy

• DOI: 10.1038/s41377-023-01286-0
• Publication Date: 2023-10-13T04:02:28Z
• Authors: Mindaugas Juodėnas; Erik Strandberg; Alexander Grabowski; Johan Gustavsson; Hana Šípová-Jungová; Anders Larsson; Mikael Käll
• Keywords: Biophotonics; Collimated light; Nanophotonics

Flat metaoptics components are looking to replace classical optics elements and could lead extremely compact biophotonics devices if integrated with on-chip light sources detectors. However, using metasurfaces shape into wide angular range wavefronts high efficiency, as is typically required in high-contrast microscopy applications, remains a challenge. Here we demonstrate curved GaAs metagratings on vertical-cavity surface-emitting lasers (VCSELs) that enable illumination total internal reflection dark field microscopy. Based an unconventional design circumvents the aspect ratio dependent etching problems monolithic integration, off-axis emission centred at 60° air 63° glass > 90% 70% relative deflection respectively. The resulting laser beam collimated out-of-plane but maintains Gaussian divergence in-plane, long narrow area. We show metagrating-integrated VCSELs of different kinds can be combined rapid switching between dark-field illumination. Our approach provides versatile solution for imaging compatible conventional setups devices, such portable microscopy, NIR-II bioimaging, lab-on-a-chip devices.