Large depth range resolution model for MLA-based light field microscope optimization

Light field microscope has emerged as a rapid, scan-free volumetric imaging tool by inserting a microlens array into the imaging path. It has demonstrated attractive advantages in observing dynamic neuronal activities and vascular network. However, the fast-volumetric imaging speed comes at the expense of resolution. Although different optical structures have been proposed, theoretical models for calculating the resolution along the targeted depth range are lacking, which makes it difficult for researchers like biologists to choose appropriate imaging systems for their specific applications. In this paper, theoretical resolution models covering the large depth range are proposed for light field microscopes with different optical architectures to optimize their design and applications quantitatively. By analyzing the imaging characteristics of a point source located at different depths and exploring the relationship between the imaging spot diameter on the sensor and its depth, the theoretical models are established to derive the lateral-axial resolution directly using the parameters of optical components. The correctness of the theoretical models is verified by both simulations and real imaging systems. In addition, a system design guidance using the proposed theoretical resolution model is provided by imaging fluorescent microspheres and tumor cells. In brief, the theoretical models can evaluate the resolution quantitatively and provide design guidance adapting to the applications, which are very beneficial to the development of light field microscopes.