We study the controllable output field generation from a cavity magnomechanical resonator system that consists of two coupled microwave resonators. The first cavity interacts with a ferrimagnetic yttrium iron garnet (YIG) sphere providing the magnon-photon coupling. Under a passive cavities configuration, the system displays high absorption, prohibiting output transmission even though the dispersive response is anomalous. We replace the second passive cavity with an active one to overcome high absorption, producing an effective gain in the system. We show that the deformation of the YIG sphere retains the anomalous dispersion. Further, tuning the exchange interaction strength between the two resonators leads to the system's effective gain and dispersive response. As a result, the advancement associated with the amplification of the probe pulse can be controlled in the proximity of the magnomechanical resonance. Furthermore, we find the existence of an upper bound for the intensity amplification and the advancement of the probe pulse that comes from the stability condition. These findings may find potential applications for controlling light propagation in cavity magnomechanics.
We study the controllable output field generation from a cavity magnomechanical resonator system that consists of two coupled microwave resonators. The first cavity interacts with a ferrimagnetic yttrium iron garnet (YIG) sphere providing the magnon-photon coupling. Under a passive cavities configuration, the system displays high absorption, prohibiting output transmission even though the dispersive response is anomalous. We replace the second passive cavity with an active one to overcome high absorption, producing an effective gain in the system. We show that the deformation of the YIG sphere retains the anomalous dispersion. Further, tuning the exchange interaction strength between the two resonators leads to the system's effective gain and dispersive response. As a result, the advancement associated with the amplification of the probe pulse can be controlled in the proximity of the magnomechanical resonance. Furthermore, we find the existence of an upper bound for the intensity amplification and the advancement of the probe pulse that comes from the stability condition. These findings may find potential applications for controlling light propagation in cavity magnomechanics.
PT-symmetric cavity magnomechanics with gain-assisted transparency and amplification
We investigate magnomechanically induced transparency in a parity-time-symmetric cavity magnomechanical system with traveling-field-induced non-Hermiticity. The setup consists of a microwave cavity mode coupled to magnons in a single-crystal yttrium iron garnet sphere, which in turn are hybridized with a vibrational mechanical mode through magnetostrictive interaction. In the Hermitian regime, strong photon-magnon coupling generates a single transparency window in the cavity transmission, which splits into a doublet when the magnon is coherently hybridized with the mechanical mode via magnomechanical coupling. This establishes a versatile platform in which the transparency spectrum can be engineered from single- to multi-window response using experimentally accessible, scaled magnomechanical interactions. When a non-Hermitian coupling is introduced, the system enters a parity-time-broken regime in which the transparency ceases to be purely passive and becomes gain assisted, leading to asymmetric transmission with amplification on one side of the resonance and enhanced absorption on the other. By tuning the cavity detuning, we convert magnomechanical transparency into Fano-type line shapes with strongly non-Lorentzian phase dispersion and map their deformation into asymmetric, gain-assisted Fano ridges in the joint space of probe and magnon detunings. Finally, we analyze the associated group delay and show that both slow- and fast-light behavior can be widely tuned by varying the photon-magnon and magnomechanical couplings together with the non-Hermitian strength, highlighting parity-time-symmetric cavity magnomechanics as a promising platform for reconfigurable quantum signal processing and enhanced sensing.
We investigate the absorption and transmission properties of a weak probe field under the influence of a strong control field in a cavity magnomechanical system. The system consists of two ferromagnetic-material yttrium iron garnet (YIG) spheres coupled to a single cavity mode. In addition to two magnon-induced transparencies (MITs) that arise due to magnon-photon interactions, we observe a magnomechanically induced transparency (MMIT) due to the presence of nonlinear magnon-phonon interaction. We discuss the emergence of Fano resonances and explain the splitting of a single Fano profile to double and triple Fano profiles due to additional couplings in the proposed system. Moreover, by considering a two-YIG system, the group delay of the probe field can be enhanced by one order of magnitude as compared with a single-YIG magnomechanical system. Furthermore, we show that the group delay depends on the tunability of the coupling strength of the first YIG with respect to the coupling frequency of of the second YIG, and vice versa. This helps to achieve larger group delays for weak magnon-photon coupling strengths.
Abstract In this paper, we propose a theoretical scheme to investigate the magnomechanically induced transparency (MMIT) phenomenon, Fano resonances, and slow/fast light effects in a hybrid cavity magnomechanical system. The magnomechanical system consists of two cavities: the principal cavity contains two ferromagnetic yttrium iron garnet (YIG) spheres, and the auxiliary cavity contains an atomic assembly. These two cavities are connected via photon tunneling, with the principal cavity being driven by two electromagnetic fields. The photon-magnon and phonon-magnon couplings are responsible for the magnon-induced transparency (MIT) and MMIT observed in the probe output spectrum. Furthermore, we examine the impacts of tunneling coupling, atom-photon coupling, and the magnetic field on the absorption, dispersion, and transmission spectra. We provide an explanation of the mechanism behind the Fano resonance phenomenon. Additionally, we address the phenomenon of slow and fast light propagation. Moreover, we demonstrate that the group delay of the probe field can be enhanced by increasing the photon tunneling strength. We also show that the slow light profile is reduced by adjusting the atom-photon coupling strength. This model is experimentally feasible, and we anticipate that these findings have potential applications in quantum information processing and communication.
In this paper, we propose a theoretical scheme to investigate the magnomechanically induced transparency (MMIT) phenomenon, Fano resonances, and slow/fast light effects in a hybrid cavity magnomechanical system. The magnomechanical system consists of two cavities: the principal cavity contains two ferromagnetic yttrium iron garnet (YIG) spheres, and the auxiliary cavity contains an atomic assembly. These two cavities are connected via photon tunneling, with the principal cavity being driven by two electromagnetic fields. The photon-magnon and phonon-magnon couplings are responsible for the magnon-induced transparency (MIT) and MMIT observed in the probe output spectrum. Furthermore, we examine the impacts of tunneling coupling, atom-photon coupling, and the magnetic field on the absorption, dispersion, and transmission spectra. We provide an explanation of the mechanism behind the Fano resonance phenomenon. Additionally, we address the phenomenon of slow and light propagation. Moreover, we demonstrate that group delay of the probe field can be improved by increasing photon tunneling strength. We also show that the slow light profile is decreased by adjusting the atom-photon coupling strength. This model is experimentally feasible. We hope these findings have the potential to be applied to the processing of quantum information and communication.
We theoretically explore the tunability of magnomechanically induced transparency (MMIT) phenomenon and fast-slow light effect in a hybrid cavity magnomechanical system in which a high-quality yttrium iron garnet (YIG) sphere and an atomic ensemble are placed inside a microwave cavity. In the probe output spectrum, we can observe magnon-induced transparency (MIT) and MMIT due to the photon-magnon and phonon-magnon couplings. We further investigate the effect of atomic ensemble on the absorption spectrum. The results show that better transparency can be obtained by choosing appropriate atomic ensemble parameters. We give an explicit explanation for the mechanism of the Fano resonance phenomenon. Moreover, we discuss phenomena of slow-light propagation. The maximum group delay increases significantly with the increasing atom–cavity coupling strength, and the conversion between slow light and fast light can also be achieved by adjusting the atom–cavity coupling strength. These results may have potential applications for quantum information processing and high precision measurements.
PT-assisted control of Goos-Hänchen shift in cavity magnomechanics
We propose a scheme to manipulate the Goos-Hänchen shift (GHS) of a reflected probe field in a non-Hermitian cavity magnomechanical system. The platform consists of a yttrium-iron-garnet sphere coupled to a microwave cavity, where a strong microwave drive pumps the magnon mode and a weak field probes the cavity. The traveling field's interaction with the magnon induces gain, yielding non-Hermitian dynamics. When the traveling field is oriented at π/2 relative to the cavity's x-axis, the system realizes PT symmetry; eigenvalue analysis reveals a third-order exceptional point (EP3) at a tunable effective magnon-photon coupling. Under balanced gain-loss and finite effective magnomechanical coupling, we demonstrate coherent control of the GHS by steering the system across the PT-symmetric transition and through EP3 via the effective magnon-photon coupling, enabling pronounced enhancement or suppression of the lateral shift. Furthermore, we show that without effective magnomechanical coupling, the system exhibits a second-order exceptional point (EP2) with a distinct GHS phase transition. This phase transition vanishes when the effective magnomechanical coupling exceeds a parametric threshold, where strong absorption at resonance suppresses the GHS. We also identify the intracavity length as an additional control parameter for precise shift tuning. Notably, the PT-symmetric configuration yields substantially larger GHS than its Hermitian counterpart. These results advance non-Hermitian magnomechanics and open a route to GHS-based microwave components for quantum switching and precision sensing.