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

Figure 8

MPM images of a tissue mimicking phantom using power-matched (~15 mW at the back aperture) annular (a) and Gaussian (b) beam illumination at ~550 μm subsurface. Field of view ~250 × 250 μm²; (c) comparison of the signal-to-background ratio (SBR) extracted from MPM images at different imaging depths. The SBR is normalized to the Gaussian SBR at each imaging depth to show relative improvement in contrast. Each image was divided into 16 nonoverlapping regions of interest of identical size.

(a)

(b)

(c)