Frequency conversion by exploiting time in transformation optics
Frequency conversion by exploiting time in transformation optics
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DOI：
10.1088/2040-8978/13/2/024007
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发表时间：
2011-02-01
影响因子：
2.1
通讯作者：
Thompson, Robert T.
中科院分区：
文献类型：
--
作者：
Cummer, Steven A.;Thompson, Robert T.
变换光学的基本框架描述了如何通过复杂的材料参数在物理上实现电磁场的坐标变换。这种方法包括转换时间和空间的可能性，但这种转换的应用仍然相对未被探索。在这里，我们分析了一维空间变化的时间变换的材料特性和波的影响。这种转换的结果在相对简单的电磁材料参数定义的各向同性介电常数与随时间变化的磁电耦合常数。我们表明，在这种介质中产生的波和场的行为是什么预期的变换，即输入频率被缩放到一个新的和任意的输出频率定义的整体幅度的时间变换。虽然实现这样的介质所需的参数是复杂的，我们描述了如何使用外部可调电磁超材料方法所需的时变磁电耦合是可行的。
The fundamental framework of transformation optics describes how coordinate transformations on electromagnetic fields can be physically realized through complex material parameters. This approach includes the possibility of transforming time as well as space, but the applications of such transformations remain relatively unexplored. Here we analyze the material properties and wave effects of a one-dimensional spatially varying time transformation. This transformation results in relatively simple electromagnetic material parameters defined by isotropic dielectric constants with a time-varying magnetoelectric coupling constant. We show that the resulting wave and field behavior in this medium is what is expected from the transformation, namely that an input frequency is scaled to a new and arbitrary output frequency defined by the overall magnitude of the time transformation. While the parameters required to realize such a medium are complex, we describe how the needed time-varying magnetoelectric coupling is feasible using an externally tunable electromagnetic metamaterials approach.