Electromagnetic Signal Propagation Through Lossy Media

It is commonly believed that electromagnetic waves cannot propagate in lossy conductive media and that they quickly decay inside such media over short length scales of the order of the so-called skin depth. In this chapter, I demonstrate that this common belief is incorrect if the conductive medium is stratified. In fact, surface electromagnetic waves in stratified lossy conductive media may have propagating character, and the propagation length of such waves may be considerably larger than the skin depth. 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. For example, materials such as graphite and silicon seem to be ideal in underwater vehicle (UV) nanophotonics applications. In addition, experimental realizations of this phenomenon in the radio frequency (RF) domain have led to the development of novel underwater communication and imaging techniques.