Table 1 Comparison of a slanted nanoslit array lens with superoscillatory lenses: sub-Abbe-limit beam focusing at far-field
Type of lens and ambient | Materials | Size (µm) | Working wavelength, λ (nm) | Spot size, FWHM | Focal length | Power ratio | References |
|---|---|---|---|---|---|---|---|
Slanted nanoslit array in air | Air/Ag/glass | 5.6 | 633 325 | 210 nm (0.33λ) 120 nm (0.37λ) | 1.6 µm (2.5λ) 1.3 µm (4λ) | 4.8% | This work |
Super-oscillatory in air | Air/Au/glass | 40 | 405 | 185 nm (0.45λ) | 10 µm (25λ) | – | [37] |
Super-oscillatory in GaP (n = 3.72) | GaP/metal/glass | 42 | 473 | 57 nm (0.12λ) | 5 µm (11λ) | 1.8% | [38] |