Exosens Unveils Laser Method for Etching Nanostructures at 300 nm

A Study on Parallel Laser Etching in Transparent Media

On July 7, 2026, Exosens published a study conducted in scientific partnership focusing on the direct fabrication of optical nanostructures in transparent materials using femtosecond lasers. The study, titled 'De-coherent Parallel Laser Processing of Ultradense Nanopores for High-Density, Large-Area 3D Optical Phase Encoding', was released in Nature Communications in 2026. This research addresses the technical challenges associated with multi-focus parallel etching: when multiple laser beams operate simultaneously, interference between adjacent foci degrades the quality and precision of the manufactured structures.

An Engineering Strategy to Reduce Optical Interferences

The study introduces an approach called De-coherent Parallel Direct Laser Writing (Dc-PDLW) aimed at mitigating interference effects. This method employs a band-segmentation hologram (SSP) to generate a controlled multi-focus light field, combined with a binary mask that assigns orthogonal polarization states to different foci in order to eliminate interferences between adjacent foci. In sapphire crystals, this approach achieved a pore spacing of about 300 nanometers (λ/4), compared to about 545 nanometers with an iterative algorithm and 601 nanometers in conventional point-by-point etching.

Optical Validation of Manufactured Structures

The study utilized a Phasics SID4 wavefront sensor to measure the optical phase changes induced by the nanostructures after their fabrication. These measurements demonstrated that the reduced spacing between pores leads to a progressive increase in refractive index modulation and birefringence, validating the link between geometric design and the actual optical behavior of the structures.