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

Figure 4

The distribution of intensity, proportional to the field amplitude squared as modeled by the Fresnel-Kirchhoff integral for different annular scenarios with varying using a maximum beam waist of 1.7 mm and focal distance of 2.7 mm. is the input beam profile at aperture exit and is the simulated intensity distribution around the focal volume. Included is also to visualize the acquired diffraction pattern.