It is demonstrated that a new kind of low-loss surface electromagnetic wave may propagate along a planar surface inside a lossy medium if the medium permittivity changes continuously across such surface. Similar to surface plasmons, the wavelength of this wave may be considerably shorter than the light wavelength in free space, which may enable its applications in super-resolution microscopy and nanolithography techniques. However, unlike plasmonics-based nanophotonic devices, which are typically built using a very limited number of low loss optical materials, the newly found class of surface waves may be supported by a much broader range of lossy media. Such materials as graphite and silicon seem to be ideal in UV nanophotonics applications. The obtained results have broad applicability in other portions of the electromagnetic spectrum down to very low frequencies. For example, similar long-range surface electromagnetic radio waves are capable of propagating underwater along a sandy seabed, which may enable efficient underwater radio communication and imaging.

结果表明，如果介质介电常数在该表面上连续变化，则一种新的低损耗表面电磁波可以沿着有损耗介质内部的平面表面传播。与表面等离子体激元类似，该波的波长可能比自由空间中的光波长短得多，这可能使其在超分辨率显微镜和纳米光刻技术中得到应用。然而，与基于等离子体的纳米光子器件通常使用非常有限数量的低损耗光学材料构建不同，新发现的一类表面波可能由更广泛的有损耗介质支持。石墨和硅等材料似乎是紫外纳米光子学应用的理想选择。获得的结果在电磁频谱的其他部分具有广泛的适用性，直到非常低的频率。例如，类似的远程表面电磁无线电波能够沿着沙质海床在水下传播，这可以实现高效的水下无线电通信和成像。