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

Table 1

Results of numerical simulation for a radially polarized beam without vortex components (𝑚=0).

Transmission function; (amplitude and phase)	Transverse intensity pattern in focus, 3𝜆×3𝜆; (total and 𝑧-component)	Transverse intensity profile: total; (solid line) and 𝑧-component (dashed line)
𝐵(𝜃,𝜙) = const	FWHM = 0.544λ, FWHMz = 0.45λ
𝛿=0.05	FWHM = 0.378λ
𝜏(𝜃),  𝛿=0.2	FWHM = 0.329λ
𝜌𝜀=𝜌Δ=0.05𝜆	FWHM = 0.203λ
𝜌𝜀=0.05𝜆,; 𝜌Δ=2𝜆,  𝜇=0.3	FWHM = 0.359λ
Л Γ(3, 0), 𝜎=𝑅/2	FWHM = 0.317λ
𝜌𝜀=0.05𝜆,; 𝜌Δ=1.5𝜆,  𝜇=0.5	FWHM = 0.313λ