Figure 3
From: A special three-layer step-index fiber for building compact STED systems
Optical power distributions on the cross-section of generated dark hollow beam at different distances from output-end of the special fiber. (a) Is the optical power distribution just at the fiber output-end. From (b) to (e), the distance between fiber output-end and the visual plane increased from 100 μm to 400 μm, with a step of 100 mm.
