Table 2: Showing the FWHM and depth of focus achieved for different beam order m and for Δn = 10 × 10-3.

m Spot size (λ) Depth of focus (λ) Shift Z (λ)
2 0.57 5.12 0.88
4 0.52 15.09 1.84
6 0.49 16.48 1.91
8 0.48 18.05 2.20