Hello, Plasmons are waves formed by electron density fluctuations on a metallic surface. Basically once excited, they can propagate freely along a suitable metallic-dielectric surface, decaying relatively quickly. I'm interested in the y-axis component of the wave, perpendicular to the metallic surface. Electric field strenght is said to rapidly decay in this direction. Obviously so, if you compare it with other vector components associated with a propagating wave. But theoretically (I suppose no-one has tried to actually do this kind of measurement yet), just how tall would these electron waves be, if one were to measure their peak amplitude (height from surface) vs. average electron operator in a non-excited state occupying a similar metallic surface. The dielectric could be air (or vacuum) for instance. I take it that this is not just a mathematical trick and that the electron plasma oscillation does occupy actual space along the y-axis also as it propagates. What say you?