A Semi-Classical View on Epsilon-Near-Zero Resonant Tunneling Modes in Metal/Insulator/Metal Nanocavities
| Autor: | Milan Palei, Vincenzo Caligiuri, Giulia Biffi, Roman Krahne, Sergey Artyukhin |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Materials science
Physics::Optics FOS: Physical sciences Bioengineering Insulator (electricity) 02 engineering and technology Metal-insulator-metal Applied Physics (physics.app-ph) Metal Mesoscale and Nanoscale Physics (cond-mat.mes-hall) General Materials Science Quantum tunnelling Condensed Matter - Mesoscale and Nanoscale Physics Condensed matter physics Mechanical Engineering Metamaterial Physics - Applied Physics General Chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 3. Good health visual_art visual_art.visual_art_medium Condensed Matter::Strongly Correlated Electrons 0210 nano-technology Physics - Optics Optics (physics.optics) |
| Zdroj: | Nano Letters |
| DOI: | 10.48550/arxiv.2004.09908 |
| Popis: | Metal/Insulator/Metal nanocavities (MIMs) are highly versatile systems for nanometric light confinement and waveguiding, and their optical properties are mostly interpreted in terms of surface plasmon polaritons. Although classic electromagnetic theory accurately describes their behavior, it often lacks physical insight, letting some fundamental aspects of light interaction with these structures unexplored. In this work, we elaborate a quantum mechanical description of the MIM cavity as a double barrier quantum well. We identify the square of the imaginary part of the refractive index of the metal as the optical potential, and find that MIM cavity resonances are suppressed if the ratio n/\k{appa} exceeds a certain limit, which shows that low n and high \k{appa} are desired for strong and sharp cavity resonances. Interestingly, the spectral regions of cavity mode suppression correspond to the interband transitions of the metals, where the optical processes are intrinsically non-Hermitian. The quantum treatment allows to describe the tunnel effect for photons, and reveals that the MIM cavity resonances can be excited by resonant tunneling via illumination through the metal, without the need of momentum matching techniques such as prisms or grating couplers. By combining this analysis with spectroscopic ellipsometry on experimental MIM structures, and by developing a simple harmonic oscillator model of the MIM for the calculation of its effective permittivity, we show that the cavity eigenmodes coincide with low-loss zeros of the effective permittivity. Comment: 33 pages, 7 figures |
| Databáze: | OpenAIRE |
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