蜂巢光子晶格中光波的无衍射和反常折射  

Non-diffraction propagation and anomalous refraction of light wave in honeycomb photonic lattices

作　　者：饶冰洁 刘圣[1] 赵建林[1] 

机构地区：[1]西北工业大学理学院,陕西省光信息技术重点实验室,西安710072

出　　处：《物理学报》2017年第23期185-191,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61675168,11634010);国家自然科学基金委员会中国工程物理研究院联合基金(批准号:U1630125)资助的课题~~

摘　　要：空间频率模式的光子带隙反映了光波在周期性结构中的线性传输特性.以这种线性传输特性为基础,研究了蜂巢光子晶格中光波的无衍射和反常折射.通过详细分析带隙结构第一通带上的衍射与折射特性,得出了光波发生反常衍射和折射的入射条件.匹配不同的入射条件,数值模拟了光波的无衍射传输和反常折射现象.结果表明:将入射光束的波矢设置在蜂巢晶格布里渊区中正常、反常衍射区的交界处,可使高斯光束沿x轴、y轴方向的衍射得到有效抑制;以多光束干涉场作为入射光场,可对蜂巢晶格进行模式匹配,激发第二布里渊区的传输模式;进一步将模式匹配后入射光场的波矢设置在反常折射区,可实现光波的反常折射.Photonic band-gap of light wave in spatial frequency model depicts the linear propagation characteristics of the light wave in period structures, based on which the linear diffraction and refraction of light are defined. In this paper, we numerically study the non-diffraction propagation and anomalous refraction of light waves in honeycomb photonic lattices according to the diffraction relationship of the photonic band-gap. By calculating the photonic band-gap structure, the linear propagation characteristics in the first transmission band are analyzed. The first Brillouin zone of the honeycomb lattice can be divided into different diffraction （Dx and Dy） and refraction regions （Δx and Δy）, according to the definitions of light diffraction and refraction along the x-and y-axis. Light wave can present normal, anomalous diffraction and even non-diffraction when the wave vector matches the regions of Dx, y 〈 0, Dx, y 〉 0 and Dx, y=0, respectively. And the wave experiences the positive, negative refractions, and non-deflection when the refraction region meets the conditions：Δx, y 〈 0, Δx, y 〉 0 and Δx, y=0, respectively. By matching the input wave vectors to the contour lines of Dx=0 and Dy=0, we can realize the non-diffraction propagation along the x-and y-axis, respectively. When the input wave vector is set to be （0, 0）, the light wave experiences normal diffraction and beam size is broadened. When the wave vector matches the point where Dy=0, the diffraction in the y-axis is obviously suppressed. To totally restrain the beam diffraction, the wave vector is set to be at the point where Dx=Dy=0. There are six intersections on the contour lines of Dx=0 and Dy=0, and these intersections are named non-diffraction points. The refraction of light can be also controlled by adjusting the input wave vector. When the wave vector is located on the contours of Δy=0, light wave propagates along the x-axis, without shifting along the y-axis. To excite the negative refractions, we need to match the

关 键 词：光子晶格 光子带隙 反常衍射 负折射 

分 类 号：O734[理学—晶体学]