Manipulation Of Fano Resonances Research Articles

Fano resonance between Stokes and anti-Stokes Brillouin scattering

In recent years, the manipulation of Fano resonances in the time domain has unlocked deep insights into a broad spectrum of systems' coherent dynamics. Here, inelastic scattering of light with coherent acoustic phonons is harnessed to achieve complex Fano resonances. The sudden change of phonon momentum during reflection leads to a transition from anti-Stokes to Stokes light scattering, producing two different resonances that interfere in the measurement process. We highlight the conditions necessary to achieve such interference, revealing an underlying symmetry between photons and phonons, and verify the theory experimentally. Then, we demonstrate the possibility to characterize energy and coherence losses at rough interfaces, thus providing a mechanism for nondestructive testing of interface quality. Our results describe numerous unexplained observations in ultrafast acoustics and can be generalized to the scattering of light with any waves.

Enhancement and Switching of Fano Resonance in Metamaterial

AbstractExcitation and manipulation of Fano resonances in plasmonic nanostructure have attracted considerable attention due to its capability of degrees of freedom in artificial design especially for spectral positions and quality factors (Q factors). To utilize the high Q factor of Fano resonances in practical applications, their sharp peaks or dips should be well detected, which means a high intensity of resonance line shape. Thus far, the realization of Fano resonant nanostructure with both the high Q factor and the intensity to overcome the trade‐off between them remains a challenge. This study both numerically and experimentally demonstrates that the high Q factor and Fano intensity are simultaneously sustained in near‐infrared region. A Fano metamaterial consisting of gold double nanorods and film with dielectric spacer between them to enhance the Fano resonance is proposed. Due to their strong near‐field coupling, the performance of the Fano resonance is significantly improved and the intensities of in‐phase and out‐of‐phase plasmonic resonances can be flexibly manipulated by easily changing the angle of incident light. These results show a novel approach with important implications of Fano resonances for realizing practical applications in optical sensing including chemical or biomedical sensors, enhanced spectroscopy, and nonlinear optical devices.

Carrier-carrier entanglement and transport resonances in semiconductor quantum dots

We study theoretically the entanglement created in a scattering between an electron, incoming from a source lead, and another electron bound in the ground state of a quantum dot, connected to two leads. We analyze the role played by the different kinds of resonances in the transmission spectra and by the number of scattering channels, into the amount of quantum correlations between the two identical carriers. It is shown that the entanglement between their energy states is not sensitive to the presence of Breit-Wigner resonances, while it presents a peculiar behavior in correspondence to Fano peaks: two close maxima separated by a minimum for a two-channel scattering and a single maximum for a multichannel scattering. Such a behavior is ascribed to the different mechanisms characterizing the two types of resonances. Our results suggest that the production and detection of entanglement in quantum dot structures may be controlled by the manipulation of Fano resonances through external fields.