Tomography of defects in optical materials via 3D structured light Project ID: GA22-09296S Provider: Czech Science Foundation Period: Jan 01, 2022 - Dec 31, 2024 Principal Investigator: doc. RNDr. Karel Žídek Ph.D. Co-investigators P. Veselá, J. Junek, D. Tomka, L. Klein, V. Kanclíř, J. Lukeš, M. Guesmi Aims of the project: Optical elements are typically prepared from a block of the optical material by their machining, which leaves a thin surface layer of the element with defects. Such defects limit the material resistance against the high laser intensity or its mechanical robustness. A promising way to track the defects and their origin is to measure their photoluminescence (PL) signal and the PL decay. However, standard tomography of a long-lived PL decay requires an immense acquisition time. In this project, we will use an implementation of compressive sampling to overcome this barrier. We will create a new approach to PL lifetime microscopic tomography by using a 3D randomly structured light close to the Fourier plane of a lens. The tomography will enable tracking defects and sources of light losses in optical materials. We will use this new technique to understand the formation of structural defects and impurities in the SiO2-based optical glasses during their machining. Moreover, this concept can be applied to a wide range of materials, where tomography of PL lifetimes is highly interesting.