Millimetric scale two-photon Bessel-Gauss beam light sheet microscopy with three-axis isotropic resolution using an axicon lens.

Abstract:

<p><b>SIGNIFICANCE: </b>Typical light sheet microscopes suffer from artifacts related to the geometry of the light sheet. One main inconvenience is the non-uniform thickness of the light sheet obtained with a Gaussian laser beam.</p><p><b>AIM: </b>We developed a two-photon light sheet microscope that takes advantage of a thin and long Bessel-Gauss beam illumination to increase the sheet extent without compromising the resolution.</p><p><b>APPROACH: </b>We use an axicon lens placed directly at the output of an amplified femtosecond laser to produce a long Bessel-Gauss beam on the sample. We studied the dopaminergic system and its projections in a whole cleared mouse brain.</p><p><b>RESULTS: </b>Our light sheet microscope allows an isotropic resolution of in all three axes of the scanned volume while keeping a millimetric-sized field of view, and a fast acquisition rate of up to . With slight modifications to the optical setup, the sheet extent can be increased to 6 mm.</p><p><b>CONCLUSION: </b>The proposed system's sheet extent and resolution surpass currently available systems, enabling the fast imaging of large specimens.</p>