B-PHOT research paper tops downloads in Optica's Optics Express journal

A paper authored by B-PHOT researchers has emerged as one of the most downloaded articles in the March edition of Optica's Optics Express journal. Titled "Fabrication of multilevel metalenses using multiphoton lithography: from design to evaluation", the paper outlines a groundbreaking procedure for designing and fabricating multilevel metalenses using multiphoton-based direct laser writing.

The study, led by Koen Vanmol, Al Ameen Abdul Nazar, Hugo Thienpont, Francesco Ferranti, and Jürgen Van Erps, delves into the meticulous process of pushing the boundaries of this rapid and adaptable fabrication technique to achieve compact high-numerical aperture metalenses on flat substrates and optical fiber tips.

We present a procedure for the design of multilevel metalenses and their fabrication with multiphoton-based direct laser writing. This work pushes this fast and versatile fabrication technique to its limits in terms of achievable feature size dimensions for the creation of compact high-numerical aperture metalenses on flat substrates and optical fiber tips. We demonstrate the design of metalenses with various numerical apertures up to 0.96, and optimize the fabrication process towards nanostructure shape reproducibility. We perform optical characterization of the metalenses towards spot size, focusing efficiency, and optical functionality with a fiber beam collimation design, and compare their performance with refractive and diffractive counterparts fabricated with the same technology.