Volumetric two-photon microscopy with a non-diffracting Airy beam.

We demonstrate a volumetric two-photon microscopy (TPM) using the non-diffracting Airy beam as illumination. Direct mapping of the imaging trajectory shows that the Airy beam extends the axial imaging range around six times longer than a traditional Gaussian beam does along the propagation direction, while maintaining a comparable lateral width. Benefiting from its non-diffracting nature, the TPM with Airy beam illumination is able not only to capture a volumetric image within a single frame, but also to acquire image structures behind a strongly scattered medium. The volumetric specimen is mapped layer by layer under Gaussian mode, while the three-dimensional structure is projected to a single two-dimensional image under Airy mode, leading to a significantly increased acquisition speed. The performance of the TPM is evaluated employing a phantom of agarose gel imbedding fluorescent beads as well as a mouse brain slice. Finally, we showcase the penetration ability of the developed Airy TPM by imaging through a scattering environment.