Fig. 1. Normalized intensity distributions of optical field intensity in XY focal plane and XZ plane containing the optical axis, as well as theoretical results of normalized intensity curves of three-dimensional optical bubble. (a) Tightly focused hollow tubular optical field generated by azimuthally polarized incident beam; (b) Tightly focused optical field generated by radially polarized incident beam with 0/π binary phase modulation; (c) Tightly focused three-dimensional optical bubble generated by superposition of two under optimal intensity uniformity;(d) Variation curve of three-dimensional optical bubble uniformity under different energy ratios (RP/AP); (e) Normalized intensity curves of three-dimensional optical bubble along x-direction, z-direction, and c-direction

Fig. 2. Optical path schematic for the generation and detection of a tightly focused optical bubble based on single-path vector beams manipulation and gold nanoparticle scanning

Fig. 3. Experimental results of normalized intensity distributions of optical field in XY focal plane and XZ plane containing optical axis, as well as normalized intensity curves of three-dimensional optical bubble. (a) Tightly focused hollow tubular optical field generated by azimuthally polarized incident beam; (b) Tightly focused optical field generated by radially polarized incident beam with 0/π binary phase modulation;(c) Tightly focused optical bubble generated by the superposition of the two; Normalized intensity curves of three-dimensional optical bubble along (d) x-direction, (e) z-direction, and (f) c-direction