Fig. 1. Intensity and phase distribution of the incident field at the waist plane. (a) Intensity, (b) phase. Here, A=B.

Fig. 2. Schematic illustration of a strongly focusing system. The origin O of the coordinate system is taken at the geometrical focus.

Fig. 3. Gouy phase difference δ_xz on the propagation axis with different semi-aperture angles. (a) α=50°, (b) α=55°, (c) α=60°.

Fig. 4. SDVs on the propagation axis with different semi-aperture angles. (a) α=50°, (b) α=55°, (c) α=60°, (d) SDVs near a SDV singularity in (b).

Fig. 5. Gouy phase differences δ_zy and δ_yx on the y_s axis: α=60°.

Fig. 6. SDVs on the y_s axis. (a) and (b) are the same figure from different views: α=60°.

Fig. 7. (a) tSDVs and (b) transverse SDs on the focal plane.

Fig. 8. tSDVs on selected transverse planes.

Fig. 9. Rotation angles of two maxima points of the transverse SD on the transverse planes from z_s=−10λ to z_s=+10λ.