The pioneering study titled “3D micro-devices for enhancing the lateral resolution in optical microscopy” conducted by researchers from the Institute of Electronic Structure and Laser (IESL – FORTH) - Gordon Zyla, Dimitra Ladika, Vasileia Melissinaki, and Maria Farsari - in collaboration with Göran Maconi, Anton Nolvi, Ari Salmi and Ivan Kassamakov from the University of Helsinki, as well as Jan Marx from Ruhr University Bochum, was selected as Outstanding Paper by Light: Advanced Manufacturing in 2024.

Overview

The researchers found that optical microscopy, while widely utilized, faces intrinsic limitations in lateral resolution due to light diffraction. To overcome this, they developed a novel 3D micro-device incorporating a dielectric micro-sphere, which is known to enhance resolution through photonic nanojets. They explained that their device consisted of a micro-sphere supported by a cantilever above a micro-hole in a modified coverslip, making it compatible with standard optical microscopes.

They reported using femtosecond laser ablation to create the micro-hole and multi-photon lithography to fabricate the micro-sphere and cantilever with high precision. According to their findings, a Zr-based hybrid photoresist enabled the creation of a nearly perfect micro-sphere with a surface roughness of λ/8. The team evaluated the performance of the micro-device using Mirau-type coherence scanning interferometry and white light illumination at 600 nm. They observed that the device significantly improved lateral resolution beyond the diffraction limit while preserving the axial resolution, as confirmed through calibration and simulations.

Reference: Gordon Zyla, Göran Maconi, Anton Nolvi, Jan Marx, Dimitra Ladika, Ari Salmi, Vasileia Melissinaki, Ivan Kassamakov, Maria Farsari. 3D micro-devices for enhancing the lateral resolution in optical microscopy[J]. Light: Advanced Manufacturing 5, 17(2024). doi: 10.37188/lam.2024.019