Ptychography of the changes in glass by fs laser inscription

We aim to collect high-resolution three-dimensional information on the distribution of electron density in subwavelength photonic structures to convert into a refractive index. We will study samples fabricated by fs-laser writing, a technique to induce changes in transparent materials spanning void formation to 10^-3 index changes, widely employed for creating optical waveguides and scattering materials. Obtaining such high-resolution information on the induced material changes yields fundamental understanding of the writing process and the limits of its reproducibility, which directly aids design of integrated photonic circuits and deterministic scattering materials, while simultaneously exploring the limitations of near-field ptychography at ID16A.