Fig. 1. Schematic of QBB generation with an axicon.

Fig. 2. Calculated intensity profiles for an ideal axicon illuminated by a Gaussian beam. The inset shows the on-axis intensity along the propagation. Parameters for the calculated are w=2  mm, α=5°, n=1.5, and λ=1064  nm.

Fig. 3. Calculated fluence distribution for typical wavelengths for (a) α=5° and (b) α=10° at the distance zmax/2. The incident beam radius, pulse energy, and refractive index are w=2  mm, Q=100  μJ, and n=1.5, respectively.

Fig. 4. Beam diameter versus axicon base angle for typical wavelengths.

Fig. 5. Comparison of the oblate-tip axicon profile with the ideal axicon.

Fig. 6. Comparison of the peak fluence for the ideal axicon (solid line) with the peak fluence for the oblate-tip axicon (dashed line) for input beam radii of (a) 2 mm and (b) 4 mm. Parameters for the calculated are α=5.6°, n=1.5, Q=1  mJ, and λ=1064  nm.