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Universal lineshapes at the crossover between weak and strong critical coupling in Fano-resonant coupled oscillators.

Zanotto S, Tredicucci A - Sci Rep (2016)

Bottom Line: In this article we discuss a model describing key features concerning the lineshapes and the coherent absorption conditions in Fano-resonant dissipative coupled oscillators.The model treats on the same footing the weak and strong coupling regimes, and includes the critical coupling concept, which is of great relevance in numerous applications; in addition, the role of asymmetry is thoroughly analyzed.Due to the wide generality of the model, which can be adapted to various frameworks like nanophotonics, plasmonics, and optomechanics, we envisage that the analytical formulas presented here will be crucial to effectively design devices and to interpret experimental results.

View Article: PubMed Central - PubMed

Affiliation: Istituto Nazionale di Ottica - CNR, Via Nello Carrara 1, 50019 Sesto Fiorentino (FI), Italy.

ABSTRACT
In this article we discuss a model describing key features concerning the lineshapes and the coherent absorption conditions in Fano-resonant dissipative coupled oscillators. The model treats on the same footing the weak and strong coupling regimes, and includes the critical coupling concept, which is of great relevance in numerous applications; in addition, the role of asymmetry is thoroughly analyzed. Due to the wide generality of the model, which can be adapted to various frameworks like nanophotonics, plasmonics, and optomechanics, we envisage that the analytical formulas presented here will be crucial to effectively design devices and to interpret experimental results.

No MeSH data available.


Related in: MedlinePlus

Coherent perfect absorption (CPA) in the dissipative coupled oscillator model.The panels on the top represent the phase diagram of the system: on the highlighted curves (criticality conditions), CPA occurs. Moving from degenerate (δ = 0) to non-degenerate (δ ≠ 0) cases, a rearrangement of CPA conditions is observed. The spectral behaviour is encoded in the color maps on the bottom, which represent the S-matrix determinant. The position of critical curves and of the S-matrix determinant spectral lineshapes are independent of the specific Fano lineshape occurring on the transmission/reflection spectra.
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f2: Coherent perfect absorption (CPA) in the dissipative coupled oscillator model.The panels on the top represent the phase diagram of the system: on the highlighted curves (criticality conditions), CPA occurs. Moving from degenerate (δ = 0) to non-degenerate (δ ≠ 0) cases, a rearrangement of CPA conditions is observed. The spectral behaviour is encoded in the color maps on the bottom, which represent the S-matrix determinant. The position of critical curves and of the S-matrix determinant spectral lineshapes are independent of the specific Fano lineshape occurring on the transmission/reflection spectra.

Mentions: where γ− = γr − γnr − γ12, γ+ = γr − γnr + γ12, and δ = ω12 − ωc. Eq. 6 unifies and generalizes the weak and strong critical coupling concepts, which was introduced in ref. 27 for a symmetric (ξ = 0) and degenerate (ωc = ω12) coupled resonator system. These concepts are recalled in Fig. 2(a–c): on the (γ12, γr) plane the phase diagram of the degenerate system consists of well separated weak critical coupling (WCC) and strong critical coupling (SCC) curves. For parameters in the lower-left part of the phase diagram, the spectrum /detS(ω)/ has a double-dip feature, with zeroes (i.e., CPA) when the SCC curve is intersected (see path B and the corresponding spectra in panel (b)). Exploring path C, instead, the coalescence of the two CPA zeros into a single one is revealed, i.e., the crossover between SCC and WCC through an exceptional point is observed (panel (c)).


Universal lineshapes at the crossover between weak and strong critical coupling in Fano-resonant coupled oscillators.

Zanotto S, Tredicucci A - Sci Rep (2016)

Coherent perfect absorption (CPA) in the dissipative coupled oscillator model.The panels on the top represent the phase diagram of the system: on the highlighted curves (criticality conditions), CPA occurs. Moving from degenerate (δ = 0) to non-degenerate (δ ≠ 0) cases, a rearrangement of CPA conditions is observed. The spectral behaviour is encoded in the color maps on the bottom, which represent the S-matrix determinant. The position of critical curves and of the S-matrix determinant spectral lineshapes are independent of the specific Fano lineshape occurring on the transmission/reflection spectra.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4836300&req=5

f2: Coherent perfect absorption (CPA) in the dissipative coupled oscillator model.The panels on the top represent the phase diagram of the system: on the highlighted curves (criticality conditions), CPA occurs. Moving from degenerate (δ = 0) to non-degenerate (δ ≠ 0) cases, a rearrangement of CPA conditions is observed. The spectral behaviour is encoded in the color maps on the bottom, which represent the S-matrix determinant. The position of critical curves and of the S-matrix determinant spectral lineshapes are independent of the specific Fano lineshape occurring on the transmission/reflection spectra.
Mentions: where γ− = γr − γnr − γ12, γ+ = γr − γnr + γ12, and δ = ω12 − ωc. Eq. 6 unifies and generalizes the weak and strong critical coupling concepts, which was introduced in ref. 27 for a symmetric (ξ = 0) and degenerate (ωc = ω12) coupled resonator system. These concepts are recalled in Fig. 2(a–c): on the (γ12, γr) plane the phase diagram of the degenerate system consists of well separated weak critical coupling (WCC) and strong critical coupling (SCC) curves. For parameters in the lower-left part of the phase diagram, the spectrum /detS(ω)/ has a double-dip feature, with zeroes (i.e., CPA) when the SCC curve is intersected (see path B and the corresponding spectra in panel (b)). Exploring path C, instead, the coalescence of the two CPA zeros into a single one is revealed, i.e., the crossover between SCC and WCC through an exceptional point is observed (panel (c)).

Bottom Line: In this article we discuss a model describing key features concerning the lineshapes and the coherent absorption conditions in Fano-resonant dissipative coupled oscillators.The model treats on the same footing the weak and strong coupling regimes, and includes the critical coupling concept, which is of great relevance in numerous applications; in addition, the role of asymmetry is thoroughly analyzed.Due to the wide generality of the model, which can be adapted to various frameworks like nanophotonics, plasmonics, and optomechanics, we envisage that the analytical formulas presented here will be crucial to effectively design devices and to interpret experimental results.

View Article: PubMed Central - PubMed

Affiliation: Istituto Nazionale di Ottica - CNR, Via Nello Carrara 1, 50019 Sesto Fiorentino (FI), Italy.

ABSTRACT
In this article we discuss a model describing key features concerning the lineshapes and the coherent absorption conditions in Fano-resonant dissipative coupled oscillators. The model treats on the same footing the weak and strong coupling regimes, and includes the critical coupling concept, which is of great relevance in numerous applications; in addition, the role of asymmetry is thoroughly analyzed. Due to the wide generality of the model, which can be adapted to various frameworks like nanophotonics, plasmonics, and optomechanics, we envisage that the analytical formulas presented here will be crucial to effectively design devices and to interpret experimental results.

No MeSH data available.


Related in: MedlinePlus