Experimental measurement of the photonic properties of icosahedral quasicrystals
Experimental measurement of the photonic properties of icosahedral quasicrystals
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DOI：
10.1038/nature03977
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发表时间：
2005-08-18
期刊：
影响因子：
64.8
通讯作者：
Chaikin, PM
中科院分区：
文献类型：
--
作者：
Man, WN;Megens, M;Chaikin, PM
准晶体结构可能具有光学带隙特性（禁止光传播的频率范围），这使得它们非常适合光子晶体（1-3）通常考虑的科学和技术应用(4)。这种准晶体可以由两种或两种以上的介电材料构成，这些介电材料排列成准周期图案，其旋转对称性是周期性晶体（如平面上的五重对称和三维上的二十面体对称）所禁止的。由于准晶体比普通晶体具有更高的点群对称性，它们的隙中心频率更接近，隙宽度更均匀，这是形成更接近球对称的完整带隙的最佳条件。虽然以前的研究主要集中在一维和二维准晶体（4-7），其中精确的（一维）或近似的（二维）能带结构可以用数值方法计算，但三维情况下的类似计算在计算上具有挑战性，尚未进行。这里我们通过做一个实验来规避计算问题。利用立体光刻技术，我们构建了一个具有厘米尺度细胞的光子准晶体，并进行了微波透射测量。我们表明，三维二十面体准晶体具有相当大的停止间隙，尽管它们具有准周期性，但产生的简单光谱使我们能够通过实验确定其有效布里渊区的面。我们的研究证实了它们是光子带隙材料的优秀候选者。
Quasicrystalline structures may have optical bandgap properties-frequency ranges in which the propagation of light is forbidden-that make them well-suited to the scientific and technological applications for which photonic crystals(1-3) are normally considered(4). Such quasicrystals can be constructed from two or more types of dielectric material arranged in a quasiperiodic pattern whose rotational symmetry is forbidden for periodic crystals (such as five-fold symmetry in the plane and icosahedral symmetry in three dimensions). Because quasicrystals have higher point group symmetry than ordinary crystals, their gap centre frequencies are closer and the gaps widths are more uniform-optimal conditions for forming a complete bandgap that is more closely spherically symmetric. Although previous studies have focused on one-dimensional and two-dimensional quasicrystals(4-7,) where exact (one-dimensional) or approximate (two-dimensional) band structures can be calculated numerically, analogous calculations for the three-dimensional case are computationally challenging and have not yet been performed. Here we circumvent the computational problem by doing an experiment. Using stereolithography, we construct a photonic quasicrystal with centimetre-scale cells and perform microwave transmission measurements. We show that three-dimensional icosahedral quasicrystals exhibit sizeable stop gaps and, despite their quasi-periodicity, yield uncomplicated spectra that allow us to experimentally determine the faces of their effective Brillouin zones. Our studies confirm that they are excellent candidates for photonic bandgap materials.