Figure 2
Subwavelength hotspots formed at different heights above the quasicrystal array. The illumination source is a diode laser with a wavelength of 660 nm. (a) Field map at a height of 5 µm above the array. (b) and (c) Fine-scan image of the hot spot indicated in map (a) and corresponding profiles of the focus along directions parallel (blue dots) and perpendicular (red dots) to the polarization of the incident light. (d) Field map at a height of 12.5 µm above the array. (e) and (f) Fine-scan image of the hot spot indicated in map (d) and corresponding profiles of the focus along directions parallel (blue dots) and perpendicular (red dots) to the polarization of the incident light. Image and text courtesy: Appl. Phys. Lett.