Ultrasmall metal-insulator-metal nanoresonators: impact of slow-wave effects on the quality factor

Jianji Yang (1) , Christophe Sauvan (2) , Anthony Jouanin (1) , Stéphane Collin (3) , Jean-Luc Pelouard (3) , Philippe Lalanne (2)

1 Laboratoire Charles Fabry / Naphel
2 lp2n-03,lp2n-13
3 LPN - Laboratoire de photonique et de nanostructures

We study the quality factor variation of three dimensional Metal-Insulator-Metal nanoresonators when their volume is shrunk from the diffraction limit (λ /2n)3 down to a deep subwavelength scale (λ /50)3. In addition to rigorous fully-vectorial calculations, we provide a semianalytical expression of the quality factor Q obtained with a Fabry-Perot model. The latter quantitatively predicts the absorption and radiation losses of the nanoresonator and provides an in-depth understanding of the mode lifetime that cannot be obtained with brute-force computations. In particular, it highlights the impact of slow-wave effects on the Q-factor as the size of the resonator is decreased. The Fabry-Perot model also evidences that, unexpectedly, wave retardation effects are present in metallic nanoparticles, even for deep subwavelength dimensions in the quasi-static regime.

Keywords: Surface plasmons; Metamaterials; Manoresonators

Domains: Optics / Photonic; Optics [physics.optics]

Jianji Yang, Christophe Sauvan, Anthony Jouanin, Stéphane Collin, Jean-Luc Pelouard, et al.. Ultrasmall metal-insulator-metal nanoresonators: impact of slow-wave effects on the quality factor. Optics Express, 2012, 20 (15), pp.16880-16891. ⟨hal-00811646⟩