准周期光子晶体平板透镜的光会聚

Focus Achieved by a Slab Lens of Quasiperiodic Photonic Crystal

提出了一种能够实现负折射的准周期光子晶体(QPC)。该准晶光子晶体具有十二重对称性,由介质背景下空气孔的准周期阵列组成。用时域有限差分方法研究了电磁波通过该十二重准晶后的传播行为。对劈形准晶样品的研究表明,电磁波在该准晶结构中发生了负折射现象。进一步利用该准晶制成平行平板,研究了平板的表面截面对电磁波传播的影响。发现改变平板的表面截面,可以调节电磁场在板后的分布。在合适的界面条件下,准晶平板对电磁波实现了会聚。因此,在实际应用中应仔细选择适当的界面参数。

A type of quasiperiod photonic crystal （QPC） that can achieve negative refraction is proposed. The QPC has 12-fold symmetry and consists of a quasiperiod array of air-holes arranged in a dielectric background. The propagation of electromagnetic wave across the 12-fold quasicrystal is investigated by employing finite difference time domain method. Simulation on the wedge-shaped sample demonstrates that negative refraction can occur in the quasicrystal structure. Parallel QPC slab is further designed to explore the influence of surface termination of flat slab on the propagation of electromagnetic wave. The results show that by changing the surface termination of flat slab, the electromagnetic field distribution behind the slab can be modulated. Under appropriate surface condition, focusing can be obtained by the QPC slab. As a result, proper surface parameter should be carefully chosen for practical applications.