Garcia N, Nieto-Vesperinas M
Laboratorio de Fisica de sistemas Pequeños, Consejo Superior de Investigaciones Cientificas, Serrano 144, Madrid 28006, Spain.
Phys Rev Lett. 2002 May 20;88(20):207403. doi: 10.1103/PhysRevLett.88.207403. Epub 2002 May 3.
By means of an analysis on evanescent waves in left-handed materials (LHM), we show that within a slab of such a medium, sandwiched between two positive refraction media, there is amplification of evanescent waves in ideal lossless, dispersiveless media; however, contrary to previous claims, this is limited to a finite width of the slab so that it prevents their restoration and perfect focusing. We illustrate this by considering their coupling to propagating waves through a tunnel barrier containing a slab of LHM. Further, we show that the effect of absorption, necessarily present in such materials, may drastically change any evanescent amplifying wave into a decaying one.
通过对左手材料（LHM）中倏逝波的分析，我们表明，在夹于两种正折射介质之间的这种介质平板内，在理想无损、无色散介质中倏逝波会得到放大；然而，与先前的说法相反，这仅限于平板的有限宽度，因此它会阻止倏逝波的恢复和完美聚焦。我们通过考虑它们通过包含左手材料平板的隧道势垒与传播波的耦合来说明这一点。此外，我们表明，这种材料中必然存在的吸收效应可能会将任何倏逝放大波急剧转变为衰减波。
