Figure 2: Examples of quasi-random cells.
From: Deterministic quasi-random nanostructures for photon control
Each cell was designed to concentrate the spectral energy into different regions in k-space. The scale bars of (a), (b) and (c) are 4 μm, 2 μm and 2 μm, respectively. (a) Periodic lattice with ring-shaped Fourier spectrum. This kind of structure is found in some biological systems and has also been used to extract light from organic light emitting diodes. (b) Lattice with Fourier energy concentrated into a well-defined circular region. This structure could be used in broad-band out-couplers, quasi-Lambertian scatterers or to provide broad-band feedback in distributed feedback lasers. (c) Quasi-random cell designed to suppress low orders and concentrate the energy into orders that can excite quasi-guided modes. This design is useful for light-trapping applications, as shown in Figs 3, 4.
