Wavefront correction with image‐based interferometric focus sensing in two‐photon microscopy

Adaptive optics is a technology that corrects wavefront distortions to enhance image quality. Interferometric focus sensing (IFS), a relatively recently proposed method within the field of adaptive optics, has demonstrated effectiveness in correcting complex aberrations in deep tissue imaging. This approach determines the correction pattern based on a single location within the sample. In this paper, we propose an image-based interferometric focus sensing (IBIFS) method in a conjugate adaptive optics configuration that progressively estimates and corrects the wavefront over the entire field of view by monitoring the feedback of image quality metrics. The sample conjugate configuration allows for the correction of multiple points across the full field of view by sequentially measuring the correction pattern for each point. We experimentally demonstrate our method on both the fluorescent beads and the mouse brain slices using a custom-built two-photon microscope. We show that our approach has a large effective field of view as well as more stable optimization results compared to the region of interest based method.