论文标题
时间调节的介电介质的强空间分散
Strong Spatial Dispersion in Time-Modulated Dielectric Media
论文作者
论文摘要
我们提出了时间调节介质介质的有效介质描述。通过在一个调制周期内采用平均字段，可以得出它们之间的关系，从而定义了不同的本构参数。在最普遍的情况下，发现有效材料是通过空间和时间分散的横向介电函数和恒定的纵向介电函数来描述的。还发现，与波数依赖性（空间分散体）相比，前者的频率依赖性很弱。讨论了这种空间分散的不同物理后果，并特别强调了弱分散近似值，发现有效材料的表现是一种谐振和各向同性的磁性型介质，没有其他纵向纵向模式，因为它通常在空间分散材料中发现。因此，时间依赖性媒体打开了一种设计动态可调的超材料的替代方法。
We present an effective medium description of time-modulated dielectric media. By taking the averaged fields over one modulation period, the relationship between them is derived, defining therefore the different constitutive parameters. In the most general situation, it is found that the effective material is described by means of a spatially and temporally dispersive transverse dielectric function and a constant longitudinal dielectric function. It has been also found that the frequency dependence in the former is weak, in comparison with its wavenumber-dependence (spatial dispersion). Different physical consequences of this spatial dispersion are discussed, with special emphasis in the weak dispersion approximation, limit in which it is found that the effective material behaves as a resonant and isotropic magnetodielectric medium with no additional longitudinal mode, as it is commonly found in spatially dispersive materials. Time-dependent media opens therefore an alternative way of designing dynamically tunable metamaterials.
