Reflective multi-immersion microscope objectives inspired by the Schmidt telescope

Voigt, F.; Reuss, A. M.; Naert, T.; Hildebrand, S.; Hotz, A. L.; Whitehead, L.; Bahl, A.; Neuhauss, S. C. F.; Roebroeck, A.; Stoeckli, E. T.; Lienkamp, S. S.; Aguzzi, A.; Helmchen, F.

doi:10.1101/2022.10.13.511906

bioRxiv · 10.1101/2022.10.13.511906

Reflective multi-immersion microscope objectives inspired by the Schmidt telescope

Voigt, F.·Reuss, A. M.·Naert, T.·Hildebrand, S.·Hotz, A. L.·Whitehead, L.·Bahl, A.·Neuhauss, S. C. F.·Roebroeck, A.·Stoeckli, E. T.·Lienkamp, S. S.·Aguzzi, A.·Helmchen, F.

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Abstract

Rapid advances in tissue clearing protocols have begun to outpace the capabilities of existing microscope objectives: High-resolution imaging inside cm-sized cleared samples is often not possible as it requires multi-immersion objectives with high numerical aperture (NA > 0.7), long working distance (WD > 10 mm) and a large field-of-view (FOV > 1 mm). Here, we introduce a novel mirror-based optical design, the "Schmidt objective", which meets all these criteria despite containing only two optical elements. It consists of a spherical mirror in contact with the immersion medium and an aspherical correction plate. We showcase a multi-photon variant of a Schmidt objective that reaches NA 1.08 at an refractive index of 1.56 and demonstrate its versatility by imaging fixed samples in a wide range of immersion media ranging from air and water to BABB, DBE, and ECI. In addition, we demonstrate in vivo imaging by recording neuronal activity in larval zebrafish.

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Voigt, F., Reuss, A. M., Naert, T., Hildebrand, S., Hotz, A. L., Whitehead, L., Bahl, A., Neuhauss, S. C. F., Roebroeck, A., Stoeckli, E. T., Lienkamp, S. S., Aguzzi, A., Helmchen, F.. 2022-10-17. Reflective multi-immersion microscope objectives inspired by the Schmidt telescope. https://doi.org/10.1101/2022.10.13.511906

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