Fig. 2

UAD light beams with different number of energy oscillations under the condition of NA = 0.095. e Zero oscillations, f one oscillation, g two oscillations, and h three oscillations are generated by the phases (a–d), the parameters of which can be found in Table 1. The anti-diffracting distances in the experiment are approximately 204.1λ, 2544.9λ, 5606.2λ, and 8316.1λ (i–l), and their corresponding theoretical results (e–h) are 195.7λ, 2560λ, 5592λ, and 8310λ, respectively. A–F are the points on the UAD light beams, wherein B, D, F are the switch points. a–f are their corresponding points in the experiment. All light intensities of UAD light beams are normalized to a unit value, which are indicated by the color bar (m). The color bar (n) shows the phase scale of a–d