Advances of large field-of-view two-photon microscopy system (invited)

Two-photon microscopy (TPM) imaging has the characteristics of high resolution, natural chromatography capability and large penetration depth, and plays an important role in the imaging of living animals. How to enlarge the field-of-view (FOV) of TPM while maintaining the high resolution to monitor large-scale dynamic responses in biomedical applications especially brain science, however, remains challenging. In this paper, the recent progress of large-FOV two-photon imaging technology is reviewed. The theoretical basis of achieving large-FOV TPM is elaborated from the perspective of optical invariant. Large- FOV TPM methods can be divided into three categories: FOV-edge aberration calibration with scanning relay engines, the design and manufacture of high-throughput objectives and correcting aberrations with adaptive optics. These methods have highly strengthened the capability of TPM used in large scale biomedical imaging. If further improved especially the imaging speed, large-FOV TPM will have great potential to contribute the development of life science and broaden the cognitive of large-scale biological activities. Large-FOV TPM, based on its outstanding spatial and temporal resolution, will become a powerful tool for dynamic monitoring across large-area in some applications that requires high resolution and mesoscale imaging simultaneously.