Photonic Quasicrystal LEDs
Photonic Quasicrystals employ tiling rules to precisely locate the surface patterning on an LED. This opens up a large design space enabling the exploitation of the high symmetry nature of the quasicrystals in LEDs. The bright periodic Bragg peaks formed by the diffractive properties of conventional Photonic Crystal structures can be re-arranged to form tailored far-field LED emission patterns ranging from uniform illumination to cone shaped emission .
| Illustration of a proprietary Sunflower Photonic Quasicrystal designed for far-field emission in the green. (A) SEM of the design (B) Out-of-plane far field emission highlighting the narrow cone light projection (C) Diffraction pattern of the quasicrystal indicating the circular Bragg peaks.|
By custom designing the quasicrystal structure for the desired far-field emission and the required application, the need for additional beam shaping is greatly reduced. This greatly simplifies the overall LED design providing increased efficiency, reduced size as well as reduced cost.
The use of photonic quasicrystals in LED structures has recently gained attention in the literature for their ability to generate even illumination that is independent of the direction of emission .
Mesophotonics has over 10 years experience in designing, modelling and fabrication of proprietary quasicrystals and are offering design and licensing services to LED manufacturers wishing to incorporate the benefits of photonic quasicrystals into their own LED designs.
Further information regarding the incorporation of photonic quasicrystals into LEDs can be found here.
 Zoorob, M. E. et al., “Complete and absolute photonic bandgaps in highly symmetric photonic Quasicrystals embedded in low refractive index materials”, Nature, vol. 404, 2000, Pg 740.
 Lee, T. D. M., Parker, G. J., Zoorob, M. E., Cox, S. J. and Charlton, M. D. B. (2005) design and simulation of highly symmetric photonic quasi-crystals. nanotechnology 16 pp. 2703-2706.
 Zhang, B. “Effects of the artificial GaN/air periodic nanostructures on current injected GaNbased LEDs”, Phys. Stat. Sol. (c) 2, no. 7, 2005, Pg 2858.