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Figure 5: False-color plots of the near-field transverse intensity distributions for confocal BALs of the same batch with different widths of the constriction in the middle plane (i.e., no constriction, 64, 48, and 32 μm wide, respectively). In all cases, the pump current has been around 16% above laser threshold and the lasers have been operated around 90 K in continuous-wave emission.