3D -printed high-NA catadioptric thin lens for suppression of XPM background in Stimulated Raman Scattering microscopy

Stimulated Raman Scattering (SRS) is a fast chemical imaging technique with remarkable bio-science applications. Cross Phase Modulation (XPM) is a ubiquitous non-linear phenomenon that can create spurious background signals that render difficult a high-contrast imaging in SRS measurements. The XPM-induced signal is usually suppressed using high Numerical Aperture (NA) microscope objectives or condensers to collect the transmitted excitation beam. However, these high-NA optics feature short working distances, hence they are not compatible with stage-top incubators, that are necessary to perform live-cell time-lapse experiments in controlled environments. Here,we showa 3D printed high-NAcompact catadioptric lens that fits inside stage-top incubators and allows the collection of XPM-free SRS signals. The lens delivers SRS images and spectra with a quality comparable to a signal collection with a high-NA microscope objective. We also demonstrate the compatibility of the 3D printed lens with other non-linear microscopies usually associated with SRS in multimodal microscopes.