Abstract We theoretically analyze the transmission characteristics of a magnon–photon coupling system based on ultrastrong optomechanical-like coupling via the cross-Kerr interaction. We use the definition of group delay to characterize the fast and slow light effects. It is found that the group delay of our system can be significantly improved by two to three orders of magnitude compared to previous studies in magnon–photon coupling systems, which means slow light effect can be significantly enhanced. By adjusting the driving power and frequency detuning of the microwave cavities, the magnitude and bandwidth of the group delay and transmittance can be adjusted precisely. Moreover, frequency control of slow light can be achieved by manipulating the strength of magnetic field. The influence of the cross-Kerr coupling strength of cavities on the system is also discussed in detail. The group delay of the system is close to milliseconds, while the transmittance is greatly improved. The result from this paper hopes to bring new development possibilities for the fabrication of optical memory and the construction of all-optical networks.
Abstract We theoretically analyze the transmission characteristics of a magnon–photon coupling system based on ultrastrong optomechanical-like coupling via the cross-Kerr interaction. We use the definition of group delay to characterize the fast and slow light effects. It is found that the group delay of our system can be significantly improved by two to three orders of magnitude compared to previous studies in magnon–photon coupling systems, which means slow light effect can be significantly enhanced. By adjusting the driving power and frequency detuning of the microwave cavities, the magnitude and bandwidth of the group delay and transmittance can be adjusted precisely. Moreover, frequency control of slow light can be achieved by manipulating the strength of magnetic field. The influence of the cross-Kerr coupling strength of cavities on the system is also discussed in detail. The group delay of the system is close to milliseconds, while the transmittance is greatly improved. The result from this paper hopes to bring new development possibilities for the fabrication of optical memory and the construction of all-optical networks.
We theoretically analyze the transmission characteristics of a magnon–photon coupling system with N cascaded microwave cavities. The influences of the magnon–photon coupling strength and cavity number on the transmission characteristics are the main focus of this research. With an increase in the cascaded cavity number, the slow light effect should be greatly enhanced. By changing the cavity lengths slightly in a staggered way, the group delay could be increased by an order of magnitude with a well guaranteed transmission amplitude. Group delay should be flexibly controlled because of the existence of magnon and the conversion of fast and slow light can be realized. Moreover, by properly adjusting the cavity length, we can control the frequency shifting of the output slow light and narrow the bandwidth of the output slow light, which can aid in the design of high-quality light-storage devices. We believe the results will have applications in the all-optical communications network.
We theoretically discuss the input–output characteristics of the cascaded magnon-photon system by focusing on the slow light effect caused by positive group delay. When two identical magnon-photon systems are cascaded, compared with the single cavity system, the bandwidth of the whole system is wider, but the group delay is smaller. The change of the group delay is different from that of the general linear system. Moreover, by changing the cavity length of the two microwave cavities, the system is slightly mismatched and the group delay could obviously increase. The slow light effect could be controlled by relative cavity length. The slow light effect of the mismatched double cavity system is more sensitive to external magnetic field than that of the single cavity system. The results provide a way to manipulate the transmission rate in optical information networks and a new view about the interconnection of microwave cavities.
The magnetostrictive effect provides an opportunity for exploring fundamental phenomena related to the phonon-magnon interaction. Here we show a tunable slow light in a cavity magnetomechanical system consisting of photon, magnon and phonon modes with a nonlinear phonon-magnon interaction, which originates from magnetostrictive forces. For a strong photon-magnon coupling strength, we can observe a transparency (absorption) window for the probe by placing a strong control field on the red (blue) detuned sideband of the hybridized modes, which are comprised of photons and magnons. In this work, we mainly show the characteristic changes in dispersion in the range of the transparency window. The value of group delay can be continuously adjusted by using different frequencies of magnon, which are determined by the external bias magnetic field and therefore can be conveniently tuned in a broad range. Both the intensity and the frequency of the control field have an influence on the transformation from subluminal to superluminal propagation and vice versa. Furthermore, one may achieve long-lived slow light (group delay of millisecond order) by enlarging the pump power. These results may find applications in information interconversion based on coherent coupling among photons, phonons and magnons.
Cavity optomechanics has enabled slow-to-fast light conversion, but traditional optomechanic systems suffer from limited tunability due to fixed mechanical frequencies. To address this constraint, we introduce a magnon degree of freedom into an optomechanical system, constructing a system that integrates photons, phonons, and magnons. We establish the theoretical model of the optomagnonic-Laguerre-Gaussian rotational system, and present numerical simulations of Fano resonances and group delay. By manipulating the magnon degree of freedom, we not only achieve slow-to-fast light conversion associated with magnons but also successfully realize such conversion effects associated with mechanical rotation-this achievement effectively overcomes the inherent tunability limitations of pure optomechanical systems and expands the frequency coverage of light conversion effects. Notably, we numerically demonstrate bidirectional light speed conversion (slow-to-fast and fast-to-slow) via continuous control field frequency modulation to tune cavity mode detuning. Additionally, our results show that adjusting optomagnonic parameters enables dynamic switching between slow light and fast light at multiple frequencies. This work provides a flexible platform for multi-frequency light speed control, with potential applications in all-optical networks and quantum communications.
Cavity magnomechanics (CMM) has rapidly become a new research field of cavity quantum electrodynamics for studying quantum information processing and sensing. Here, we theoretically study the magnomechanically induced transparency effect in a cavity magnomechanical system, focusing on the role of magnon squeezing in enhancing and controlling the group delay of the transmitted light. As a result, we find that the magnon number can be strongly affected by magnon squeezing, accompanied by a steerable transmission rate and controllable fast-to-slow light switching. In particular, in the photon-magnon strong-coupling scenario, the group delay of the probe field can be enhanced by about three times by using magnon squeezing compared to the case without magnon squeezing. Moreover, due to the presence of magnon squeezing, the efficiency of the second-order sideband in the photon-magnon weak-coupling scenario can also be enhanced compared to the case without magnon squeezing. These results provide tools to engineer CMM devices with magnon squeezing for, e.g., light propagation and storage, and precision measurements of weak signals.
Nonlinear interactions between optical fields and magnetic modes in cavity magnonics constitute a rich source of various nontrivial effects in optics and quantum information processing. In cavity magnonics, biased ferromagnetic material exhibits both magnetostatic and Kittle modes due to field inhomogeneity. Here, we propose a scheme for the investigation of probe field transmission profiles in cavity magnonic systems composed of a microwave cavity and a ferromagnetic material (yttrium iron garnet sphere). We report single-to-double magnon-induced transparency (MIT) dips and a sharp magnon-induced absorption peak, and demonstrate how nonlinear cross- and self-Kerr interactions can significantly enhance or suppress these phenomena. It is observed that the splitting of the MIT window occurs when we incorporate magnon–magnon mode coupling, which helps to introduce a degree of freedom to light–matter interaction problems. Moreover, we investigate the propagation of group delay in the vicinity of transparency and demonstrate how a sharp dip allows the realization of slow light for a longer period of time. We found that both the cavity–Kittle and magnon–magnon mode coupling parameters influence the propagation of group delay, which demonstrates how subluminal-to-superluminal (and vice versa) propagation phenomena may occur and transform. These findings could pave the way for future research into nonlinear effects with novel applications in cavity magnonics devices, which might be exploited for several applications such as quantum computing devices and quantum memories.