Superradiantly limited linewidth in complementary THz metamaterials on Si-membranes

Abstract

We study complementary double split ring THz resonators fabricated on a 10 mum thin Si-membrane. The linewidths of the fundamental LC-mode and dipolar mode are drastically narrowing with increased resonator spacing. The extracted decay rate of the LC-mode as a function of the resonator density shows a linear dependence, evidencing a collective superradiant effect of the resonator array. Furthermore, we show that a metamaterial can be designed for a low superradiant broadening of the resonance at high resonator densities, i.e. in the metamaterial condition. The use of a thin membrane as a substrate is crucial, since it shifts the THz surface plasmon polaritons modes to much higher frequencies, preventing them to couple to the LC mode and unveiling the superradiant broadening mechanism for a large range of lattice spacings. At higher frequencies, not interfering with the high Q LC-mode, other additional modes, which we ascribe to photonic crystal modes, form in the Si-membrane. We map the angle dependent band structure and show corresponding simulated electric field distributions.

References in corpus (5)

• A comparison of graphene, superconductors and metals as conductors for metamaterials and plasmonics
• Ultrastrong Coupling in the Near-field of Complementary Split Ring Resonators
• Superradiant Decay of Cyclotron Resonance of Two-Dimensional Electron Gases
• High quality factor, fully switchable THz superconducting metasurface
• Resonance linewidth and inhomogeneous broadening in a metamaterial array

Cited by in corpus (1)

• Non-Invasive Near-field Spectroscopy of Single Sub-Wavelength Complementary Resonators