We investigate a double cavity optomechanical system generating single and double Fano resonance (multi-Fano). By altering a single parameter, the tunnelling rate g of the middle mirror, we are able to switch between single and double Fano line shapes. The first spectral line shape is stronger in the case of multi-Fano than in the case of single Fano. Also the behaviour of the steady state value of the displacement of the middle mirror, with respect to g, heavily influences the behaviour of double Fano lines in our scheme. This tunability along with using a single pump and signal/probe laser has an added advantage in situations where only low power consumption is available. 相似文献
We introduce a model to study a symmetric nanocontact, whereby its mechanical properties can be analyzed via the vibration spectra. The model system consists of two groups of triple semi-infinite atomic chains joined by atoms in between. The matching method theoretical approach is used to calculate the coherent reflection and transmission scattering probabilities, the characteristic vibration Green functions and densities of states (DOS), for the vibration components of the individual atomic sites that constitute a complete representation of the nanocontact domain boundaries. The nanocontact observables are numerically calculated for different cases of elastic hardening and softening, to investigate how the local dynamics can respond to changes in the microscopic environment on the nanocontact domain. The analysis of the vibration spectra and the DOS demonstrate the fluctuations, related to Fano resonances, due to the coherent coupling between traveling phonons and the localized vibration modes in the nanocontact domain. 相似文献
Utilizing three‐dimensional vectorial electromagnetic simulation, we propose a new refractive index sensing mechanism based on Fano resonance enhanced two‐photon‐absorption induced luminescence (TPL). The TPL from gold nanodisk heptamer (GNDH), which is affected by the refractive index of surrounding material, is used as an example to demonstrate the sensing mechanism facilitated by Fano resonance. The sensitivity of our method is about one order of magnitude better than the conventional refractive index sensing strategy employing plasmonic Fano resonance, while the size of the sensing probe can be further reduced at the same time.
We study the dynamical scattering in one-dimensional systems with a nonlinear side-coupled defect. Such structures exhibit the nonlinear Fano resonances, where nothing can propagate through. We developed a numerical model to study dynamical scattering. According to our analysis the scattering waves become dynamically unstable in the vicinity of the nonlinear Fano resonances, due to modulational instability caused by the presence of nonlinearity. It results in a time-growing amplitude of the nonlinear defect. We also demonstrate the existence of the nonlinear quasi-localized state, supported by such structures. 相似文献
We investigate theoretically Rabi-like splitting and Fano resonance in absorption spectra of quantum dots(QDs)based on a hybrid QD-semiconducting nanowire/superconductor(SNW/SC)device mediated by Majorana fermions(MFs).Under the condition of pump on-resonance and off-resonance,the absorption spectrum experiences the conversion from Fano resonance to Rabi-like splitting in different parametric regimes.In addition,the Fano resonances are accompanied by the rapid normal phase dispersion,which will indicate the coherent optical propagation.The results indicate that the group velocity index is tunable with controlling the interaction between the QD and MFs,which can reach the conversion between the fast-and slow-light.Fano resonance will be another method to detect MFs and our research may indicate prospective applications in quantum information processing based on the hybrid QD-SNW/SC devices. 相似文献
We use semiconductor superlattices as a model system for the investigation of Fano resonances. In absorption the excitonic transitions of the Wannier–Stark ladder show the typical asymmetric line shape due to coupling to the continuum of lower-lying transitions. The unique feature of these Fano resonances is that they allow to continuously tune the key parameter – the coupling strength Γ between the discrete state and the degenerate continuum – by varying the bias voltage. Using this feature, we directly show that the Fano coupling leads to a fast polarization decay. We also investigate the dependence of the Fano parameters on the structure of the superlattice and compare with an extensive theoretical model of the resonances. 相似文献
A gold dimer structure consisting of a notched triangle nanoslice and a rectangle nanorod is proposed to produce distinct Fano resonance. Owing to the coupling between the dipole plasmon mode of the nanorod and the dipole or quadrupole plasmon mode of the nanoslice, the extinction spectrum with a deep Fano dip is formed and can be well fitted by the Fano interference model for different geometry parameters. In addition, Fano resonance of the gold dimer nanostructure also intensely depends on the polarization direction of incident light. Moreover, Fano resonance of the triangle–rod trimer is also analyzed by adding another nanorod into the former dimer and exhibits the splitting of plasmonic resonant peak in high order coupling modes. The plasmonic hybridizations in these nanostructures have been analyzed for revealing the physical origin of the Fano resonance. 相似文献
In this article, Fano lineshape whispering gallery modes were observed in the light scattering spectrum of a silicon microsphere in near-infrared telecommunication wavelengths. A simple model is presented to explain the transition from Lorentzian lineshape to the Fano lineshape resonances with the coupled-mode theory of multiple whispering gallery modes. Polar mode spacing of 0.23 nm is observed in the spectra, which correlates well with the calculated value. The quality factor of the Lorentzian and Fano resonances are on the order of 105. By using an appropriate interface design for the microsphere coupling geometries, Fano lineshape optical resonances herald novel device applications for silicon volumetric lightwave circuits. 相似文献
Localization of the center‐of‐mass (com) motion of an exciton in a disordered semiconductor structure is studied theoretically by focusing on nonlinear optical spectroscopy. A one‐dimensional tight‐binding model with diagonal disorder is applied and the Coulomb interaction is treated consistently. In the ordered situation the center‐of‐mass momentum (K) selection rule leads to only the lowest transition for K = 0. The break down of the com‐K‐selection rule produces the well known asymmetric excitonic lines of disordered semiconductors. The coupling between the lowest dominant transition to this modified com‐continuum yields Fano‐like features in the nonlinear spectra. 相似文献
Toroidal multipoles have recently been explored in various scientific communities, ranging from atomic and molecular physics, electrodynamics, and solid‐state physics to biology. Here we experimentally and numerically demonstrate a three‐dimensionsal toroidal metamaterial where two different toroidal dipoles along orthogonal directions have been observed. The chosen toroidal metamaterial also simultaneously supports Fano resonance and the classical analog of electromagnetically induced transparency (EIT) phenomena in the transmission spectra that originate from the electric–toroidal dipole and electric–magnetic dipole destructive interference. The intriguing properties of the toroidal resonances may open up avenues for applications in toroidal moments generator, sensing and slow‐light devices. 相似文献
Based on the Floquet scattering theory, a model of graphene-based electronic device is presented, in which electrical transport is controlled by adjusting Dirac fermions energy near resonance conditions. The presence of an oscillating field leads to the Fano resonance in transport through a magnetic structure in an armchair graphene nanoribbon (AGNR). The Fano resonance originates from bound states of the magnetic confinement, according to subband indices in the AGNR. The ballistic conductance is markedly affected by the Fano resonance due to the quasi-one-dimensional nature of AGNRs. The results may help realizing graphene electronics with the resonant characteristics in the conductance. 相似文献
We investigate the electronic transport properties of the
single-impurity Anderson model. By employing the cluster expansions,
the equations of motion of Green's functions are transformed into
the corresponding equation of motion of connected Green's functions,
which contains the correlation of two conduction electrons beyond
the Lacroix approximation. With the method we show that the
asymmetric line shape of zero bias conductance manifests itself as
the Fano effect, and the Kondo effect is observed in the narrow peak
of differential conductance curve of the system. The Fano and the
Kondo effects can coexist in the single-impurity Anderson model when
the impurity level is adjusted to an appropriate position. 相似文献
We studied the sharp asymmetric Fano line shape in fiber ring resonator systems and provided an explicit expression for asymmetry parameters using the physical parameters of the system. The fiber ring system was controllable and reconfigurable, allowing us to produce a variety of Fano line shapes in different configurations. Experimentally observed asymmetric spectral structures were fully reproduced using the complex-number asymmetry parameters, validating the approximations used to reduce the analytical expression for the line shape to the phenomenological Fano formula. The results may be useful in the design of on-chip application systems. 相似文献
We study the splitting of the Fano resonance in a Aharonov–Bohm interferometer with a quantum dot in each of its arms. Both intra- and inter-dot Coulomb repulsions are taken into account by employing the Keldysh nonequilibrium Green’s function technique. The single narrow Fano resonance in the noninteracting case is split into two in the presence of either intra- or inter-dot Coulomb interaction. We find that four Fano peaks emerge in the conductance or local density of states spectra when the two kinds of interactions exist simultaneously. Such behavior holds true for the accompanying broad Breit–Wigner type resonance. We also show that the positions of the Fano peaks can be tuned with the aid of the magnetic flux penetrating through the ring, which might have practical applications in device design or quantum computation. 相似文献
The optical properties and sensing performances of the molecular sensors based on plasmonic Fano‐resonance (PFR) nanostructures have been numerically investigated in detail. The on‐resonance sensor, in which the Fano‐resonance position is overlapping with the absorption‐band of the detected molecules perfectly, reveals a powerful ability to detect the molecules with a low concentration or thin thickness. By the bias‐modulation of a single‐layer graphene, the Fano‐resonance position of the nanostructures can be tuned effectively. On being modulated properly, the PFR sensor shows an ultrahigh performance because of the unprecedentedly high overlap of the Fano‐resonance position with the absorption‐band of molecules, which is enabling superior signal strength in the molecular detections based on their vibrational fingerprints. Our proposed strategy may enable the development of dynamic sensors and open exciting prospects for bio‐sensing.