Minimizing the Bright/Shadow Focal Spot Size with Controlled Side-Lobe Increase in High-Numerical-Aperture Focusing Systems

Table 4

Results of numerical simulation for the circular “+”-polarization in the presence of a second-order optical vortex (𝑚=−2).

Transmission function, 𝐵(𝜃,𝜙)	Transverse intensity in the focus, 3𝜆×3𝜆 (total and 𝑧-component)	Transverse intensity profile: total (solid line) and 𝑧-component (dashed line)
exp(−𝑖2𝜙)	FWHM = 0.38λ; FWHMz = 0.352λ
ring(𝜃)exp(−𝑖2𝜙),; 𝛿=0.05𝑅	FWHMz = 0.3λ
𝜌𝜀=0.3𝜆,; 𝜌Δ=2𝜆, 𝜇=0.3	FWHM = 0.34λ; FWHMz = 0.34λ