Fig. 1. (a) Schematic diagram of the optical path of the STED-LDW system (HWP, half-wave plate; PBS, polarizing beam splitter; DM, dichroic mirror; LP, polarizer; (b) diagram of the double HWPs and the cylindrically symmetric vector beam angle.

Fig. 2. Effects of average power, speed, and polarization on linewidth. (“W” represents the writing direction and “P” represents the polarization direction during the excitation beam processing.) (a) shows the effect of excitation beam on linewidth, with the linewidth increasing successively with the increase in power; (b) shows the effect of LDW speed on linewidth, where an increase in speed leads to a decrease in linewidth; (c) shows the effect of excitation beam polarization on the processing results.

Fig. 3. Erasure effect with different depletion beams. (a) Test patterns with solid circularly polarized depletion beam without DETC doping and with 0.5% (mass fraction) DETC doping; (b) test patterns for radially polarized depletion beam under the same conditions as (a).

Fig. 4. (a) Feature size of the nanowire processed by excitation beam under different depletion beam power. (b)–(d) show the processing results with different depletion beam intensity distributions, while other conditions remain the same.

Fig. 5. (a) The beam intensity and polarization distribution of the depletion beam at the pupil entrance; (b) the focal field distributions of the dual beams after focusing with a high numerical aperture objective lens; (c) the feature size under different depletion beam polarizations; (d) the resolution under different depletion beam polarizations.