Extreme Plasmons

Abstract Nanometric confinement of electromagnetic energy has become possible using plasmons that are quasiparticles constituted by collective oscillations of conduction band electron gas. Here, nonperturbative plasmons are modeled having large‐amplitude oscillations that approach the extreme limit set by breakdown in characteristic coherence of collective quantum electron gas oscillations. In contrast, conventional plasmons are small‐amplitude oscillations. Controlled excitation of such extreme plasmons modeled here has become realizable now with trends in ultrashort particle bunch compression. Extreme plasmons unleash unparalleled possibilities including access to unprecedented Petavolts per meter fields. In this work, an analytical model of this class of plasmons is developed based on quantum kinetic framework. A controllable extreme plasmon, the surface crunch‐in plasmon, is modeled here using a modified independent electron approximation. In this model, various quantum effects such as suppression of electron–electron interactions due to non‐classical equilibrium states at trajectory extrema are incorporated by introducing a quantum factor, .