Monitoring and manipulating neuronal activities with optical microscopy desires a method where light can be focused or projected over a long axial range so that large brain tissues (>100 [Formula: see text] thick) can be simultaneously imaged, and specific brain regions can be optogenetically stimulated without the need for slow optical refocusing. However, the micron-scale resolution required in neuronal imaging yields a depth of field of less than 10 [Formula: see text] in conventional imaging systems. We propose to use a circularly symmetric phase mask to extend the depth of field. A numerical study shows that our method maintains both the peak and the shape of the point spread function vs the axial position better than current methods. Imaging of a 3D bead suspension and sparsely labelled thick brain tissue confirms the feasibility of the system for fast volumetric imaging.
Keywords: (170.2520) Fluorescence microscopy; (170.3880) Medical and biological imaging; (170.6900) Three-dimensional microscopy.