Scatterer radius dependence of focusing properties in two-dimensional photonic quasicrystal flat lens

• The focusing properties of a photonic quasicrystal flat lens with different scatterer radii have been analyzed.
• The lenses have different scatterer radius thresholds for different wavelengths and modes.
• The dual-focusing has been found.
• Increasing scatterer radius will decrease dual-focusing image power and far-field-focusing image quality.
• Increasing scatterer radius will increase near-field-focusing image quality and dual-focusing image distance.

The focusing properties of a germanium decagonal photonic quasicrystal flat lens with different scatterer radii have been analyzed. For different wavelengths and polarization modes, the lenses have different scatterer radius thresholds resulting in different focusing properties. For a point source of light in the transverse-electric mode, we found dual-focusing occurs along the symmetry axis within a range of scattering radii. As scatterer radius increases, the dual-focusing image power and far-field-focusing image quality diminish, whereas near-field-focusing image quality, dual-focusing image distance, and the summed object-image distance all increase.