200 nm K p k$_{x}$ p 8 -8 FIG. 9. Transverse pattern of a nondiffracting beam with β = 9 . 00 µ m − $^{1}$. The beamwidth of the main central focus has Δ$_{x}$ = 109 nm and Δ$_{y}$ = 46 nm, going beyond the diffraction limit Δ$_{min}$ = 116 nm. 31