Ultrasmall volume plasmons, yet with complete retardation effects.
Nanoparticle plasmons are attributed to quasistatic oscillations with no wave propagation due to their subwavelength size. However, when located within a band-gap medium (even in air if the particle is small enough), the particle interfaces act as wave mirrors, incurring small negative retardation. The latter, when compensated by a respective (short) propagation within the particle, generates a constructive interference based resonator. The unusual wave interference in the subwavelength regime (modal volume <0.001lambda(3)) significantly enhances the Q factor, e.g., 50 vs 5.5 of the quasistatic limit.
Feigenbaum
Eyal
E
Department of Electrical Engineering, Technion, Haifa, Israel.
Orenstein
Meir
M