3D-Printedhigh-NAcatadioptric thin lens for suppression ofXPMbackground in Stimulated Raman Scattering microscopy

Stimulated Raman Scattering (SRS) is a fast chemical imaging technique with remarkable bioscience applications. Cross Phase Modulation (XPM) is a ubiquitous nonlinear 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 show a 3D printed high NA compact 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 nonlinear microscopies usually associated with SRS in multimodal microscopes.

Automated summary

The 3D printed high NA compact catadioptric lens effectively eliminates the spurious background signals induced by XPM in SRS measurements, enabling convenient collection of high-quality SRS signals. This lens not only rivals high-NA microscope objectives in signal collection, but also demonstrates compatibility with other nonlinear microscopies associated with SRS in multimodal microscopes.