Figure 6
The intensity profile in the vicinity of the focus as a function of the propagation distance z1F for the aperture sizes of 25 µm (a), 100 µm (c) in the horizontal direction. The white dashed lines indicate the coherent part of the beam with a width given by the transverse coherence length. (b), (d) Line scans of the intensity profile I(x) from (a), (c) in the focal plane at z1F = 0. The shaded region shows the coherent part of the beam with the width corresponding to the transverse coherence length in the focal plane. |