论文标题
具有平坦带的不均匀材料中的模式转换和共振吸收
Mode conversion and resonant absorption in inhomogeneous materials with flat bands
论文作者
论文摘要
将横向电磁波转化为纵向振荡的模式以及在不均匀等离子体中的波能吸收的相关谐振吸收是在等离子体物理学中广泛研究的现象。我们表明，精确的类似现象通常发生在电子和光子系统中，在不均匀势或中等参数的情况下，无分散的平坦带和分散带共存。我们证明，通过两个色散谱带和一种平面带显示模式转换和一种与$ p $极极化的电磁波相似的方式，具有两个配色条带和一种平面带显示模式转换和共振吸收的系统描述的系统，在未经磁化等离子体中，通过使用无效的IMBEDINED IMBEDDED MEDDINDIMBEDDINS计算模式转换系数，以无效的等离子体中的$ p $极极化的电磁波。我们还表明，在许多其他具有平坦频段的系统中，类似的模式转换过程，例如伪2迪拉克系统，用于一维的存根和锯齿状晶格获得的连续模型，以及具有二次频段的二维电子系统，具有二次频段和几乎平坦的频段。我们讨论了在平面材料和超材料中模式转换的一些实验含义。
Mode conversion of transverse electromagnetic waves into longitudinal oscillations and the associated resonant absorption of wave energy in inhomogeneous plasmas is a phenomenon that has been studied extensively in plasma physics. We show that precisely analogous phenomena occur generically in electronic and photonic systems where dispersionless flat bands and dispersive bands coexist in the presence of an inhomogeneous potential or medium parameter. We demonstrate that the systems described by the pseudospin-1 Dirac equation with two dispersive bands and one flat band display mode conversion and resonant absorption in a very similar manner to $p$-polarized electromagnetic waves in an unmagnetized plasma by calculating the mode conversion coefficient explicitly using the invariant imbedding method. We also show that a similar mode conversion process takes place in many other systems with a flat band such as pseudospin-2 Dirac systems, continuum models obtained for one-dimensional stub and sawtooth lattices, and two-dimensional electron systems with a quadratic band and a nearly flat band. We discuss some experimental implications of mode conversion in flat-band materials and metamaterials.
