Meta-Optical Miniscope for Multifunctional Imaging

Miniaturized microscopes (miniscopes) allow real-time imaging of neuronal activity in animal behavior studies, allowing animals to remain largely unconstrained during behavioral tasks. Canonical designs utilize either Gradient-Index (GRIN) lenses or a set of refractive lenses as the objective module for excitation and collection of fluorescence. However, GRIN lenses are often limited in optical performance due to aberrations, whereas refractive lenses provide superior optical performance but suffer from bulky and complex designs. Meta-optics, which are subwavelength diffractive optical elements, have shown potential to replace traditional solutions while also combining multiple functionalities and significantly reducing the overall footprint and weight of a system. In this work, we leverage the diverse functionalities that meta-optics can enable through their design, including large field of view (FOV), extended depth of focus (EDOF), and depth sensitivity, which expands the miniscope tool-box. These meta-optics are seamlessly integrated by replacing the traditional refractive lens assembly. Performance evaluations highlight the enhanced imaging capabilities, aligned with predesigned functionalities. Furthermore, the reduced thickness of the meta-optics can shorten the total track length of the objective module from 6.7 mm to 2.5 mm. These improvements have the potential to facilitate the development of more compact and multifunctional miniscopes.