Fig. 5

Subdiffraction-limited focusing of light with a tilted nanoslit array lens. a SEM image of an 8-slit Ag lens. Scale bar, 3 µm. b Ag lens characterized at 633 nm wavelength. NSOM scan image (top) and scan profiles (bottom). A minimal spot size is measured to be 210 nm FWHM at y = 1.57 µm. c Al lens at 325 nm wavelength. A minimal spot size of 120 nm is observed at y = 1.26 µm. d Cr lens at 325 nm wavelength. A minimal spot size of 140 nm is observed at y = 1.10 µm