X-ray tomography of glass modifications induced by fs-laser writing

The aim of this experiment is to collect high-resolution 3D information on the distribution of electron density of subwavelength photonic structures using near-field ptychography to convert into refractive index. We will study samples fabricated using fs-laser direct writing, a technique to induce permanent changes in the molecular structure of the transparent materials that is widely used in integrated photonics. Obtaining such high-resolution information on the induced material modifications yields fundamental understanding of the writing process and the limits of its reproducibility, which directly aids the design and fabrication of integrated photonic circuits and reproducible scattering materials. Furthermore, these low-contrast samples offer an opportunity to explore the limitations of metrology at ID16A.