The Cousa objective: a long working distance air objective for multiphoton imagingin vivo

AbstractTwo-photon microscopy can resolve fluorescence dynamics deep in scattering tissue, but applying this techniquein vivois limited by short working distance water-immersion objectives. Here we present an ultra long working distance (20 mm) air objective called the Cousa objective. It is optimized for performance across multiphoton imaging wavelengths, offers a >4 mm2FOV with submicron lateral resolution, and is compatible with commonly used multiphoton imaging systems. We share the full optical prescription, along with data on real world performance includingin vivocalcium imaging in a range of species and approaches.