FASER: A TOOL TO SIMULATE PSF DISTORTIONS IN STED MICROSCOPY

We introduce Faser, a software package developed in Python as a plugin for the open-source napari platform, designed to simulate the excitation point spread functions (PSFs) of microscopes. Using a full-vectorial computational approach to simulate the electromagnetic fields within the focal region, it makes precise predictions and allows detailed analyses of excitation PSFs. Faser is intended as a pedagogical tool enabling users to explore the impact of various geometrical and optical parameters of practical importance on imaging performance. It supports the modeling of complex beam profiles, including donut and bottle-shaped beams, which are instrumental in advanced microscopy techniques such as Stimulated Emission Depletion (STED) microscopy. Through specific simulations and accessible illustrations, we showcase Faser’s capabilities in replicating the distinctive properties of STED beams, making it a valuable resource for researchers and students in optical microscopy to explore and optimize high-resolution imaging techniques.