Annular Beam Shaping in Multiphoton Microscopy to Reduce Out-of-Focus Background

Figure 5

The calculated (solid line) along the -axis as a function of b/B obtained from the theoretical simulations for a 0.7 NA objective. To maintain a focal extent within twice the diffraction-limited performance, should be less than 2 μm (dashed line). Thus, annular ratios should be kept <0.6 to avoid loss in -resolution.