In the past few years, the emerging photon-magnon dissipative coupling offers us an effective way to design and exploit losses to fulfill quantum tasks in hybrid cavity magnonics systems. In this paper, we theoretically investigate the dissipative-coupling-induced transparency (DCIT) and the enhancement of the high-order sidebands in a dissipative photon-magnon coupling system with Kerr nonlinearity. We find that the DCIT can be observed with both a weak and strong driving field. Due to the existence of the Kerr nonlinearity and introduction of the strong driving field of magnon, the sidebands can be enhanced highly by choosing the optimized parameters. In order to find the optimized parameters to enhance sidebands, we utilize the eigenvalues of the effective Hamiltonian to find the critical point of the stability region, near which sidebands can be enhanced in maximal degree.
In the past few years, the emerging photon-magnon dissipative coupling offers us an effective way to design and exploit losses to fulfill quantum tasks in hybrid cavity magnonics systems. In this paper, we theoretically investigate the dissipative-coupling-induced transparency (DCIT) and the enhancement of the high-order sidebands in a dissipative photon-magnon coupling system with Kerr nonlinearity. We find that the DCIT can be observed with both a weak and strong driving field. Due to the existence of the Kerr nonlinearity and introduction of the strong driving field of magnon, the sidebands can be enhanced highly by choosing the optimized parameters. In order to find the optimized parameters to enhance sidebands, we utilize the eigenvalues of the effective Hamiltonian to find the critical point of the stability region, near which sidebands can be enhanced in maximal degree.
Dissipative coupling generally results in complex effective spin–photon interactions, which have significant applications in nonreciprocal transport and enhanced sensing technologies. In this paper, we consider the cooperative effect of coherent and dissipative magnon–photon couplings in an open cavity magnonical system. By enhancing the magnon Kerr nonlinearity with an additional microwave driving field, magnon-induced nonlinear phenomena such as bistability and second-order sideband generation (SSG) can be obtained. By continuously adjusting the ratio of dissipative to coherent coupling strengths, nonreciprocal SSG is observed near the zero-damping condition. Furthermore, the results show that the isolation ratio (the efficiency of the nonreciprocal SSG) can reach up to 82 dB. In addition, increasing the power of the microwave driving field broadens the control range of the dissipative coupling strength, within which the isolation ratio remains above 10 dB. These findings have potential implications for high-precision measurement and on-chip manipulation of light propagation.
We investigate the enhanced generation of the optical second-order sideband (OSS) via magnon Kerr nonlinearity from a cavity magnonical hybrid system consisting of a single small yttrium iron garnet (YIG) crystal sphere and a three-dimensional (3D) rectangular cavity driven with a weak probe and a strong control field. Beyond the linear approximation, we solve the nonlinear Heisenberg–Langevin equations for achieving the analytical solutions by employing the perturbation technique. Using the experimentally achievable parameter settings, we demonstrate that the OSS generation can be significantly enhanced via increasing the magnon Kerr nonlinearity even if the coupling between the cavity and magnon is weak. Interestingly, two-color OSS generation can be observed when the cavity-magnon coupling is in the strong-coupling regime, which results from the magnonical polaritons induced by the hybrid of cavity and magnon modes. The present results illustrate the potential to utilize magnon Kerr nonlinearity for enhancing optical higher-order sidebands and controlling optical frequency combs, as well as to guide the design of experimental implementation.
Achieving strong optical nonlinearity in a low excitation power level is crucial in micro- and nanophotonics, central to many applications. Here, we explore optical linear and nonlinear responses in a single quantum dot (QD) embedded into a single-mode cavity under the effect of an external magnetic field and a continuous-wave laser excitation in the weak-coupling regime. Using experimentally realistic parameters, we find that the magnetic field introduced in such a coupled cavity-QD system can drastically modify the properties of photons and thus can be employed as a flexible control parameter. Especially, the enhanced optical Kerr nonlinearity can be achieved by tuning the applied magnetic field appropriately, which can reach over 11-fold improvement as compared to the case without the magnetic field. Physically, this is the consequence of the magnetic-field-induced resonance shifts and the cavity-field-mediated interferences. As an example of its applications, in the basis of this attainable strong Kerr nonlinearity, we show a feasible way of generating an optical high-order sideband efficiently, with small sideband spacing, as small as a few tens of megahertz, and low input excitation power, as low as a few nanowatts. Moreover, the manipulation of the high-order sideband is also discussed by changing the magnetic field from 0 to 3 T, where the variation of the sideband power is in good agreement with that of the Kerr nonlinearity. Considering realistic experimental conditions we elaborate the possible implementation of our proposal. In addition to being of fundamental interest, the results of our paper hold potential in optical frequency combs, nonlinear optics, and high precision measurement.
The nonlinearity of magnons plays an important role in the study of an optomagnonical system. Here in this paper, we focus on the high-order sideband and frequency comb generation characteristics in the atom coupled optomagnonical resonator. We find that the atom-cavity coupling strength is related to the nonlinear coefficients, and the efficiency of sidebands generation could be reinforced by tuning the polarization of magnons. Besides, we show that the generation of the sidebands could be suppressed under the large dissipation condition. This study provides a novel way to engineer the low-threshold high-order sidebands in hybrid optical microcavities.
Abstract In this paper, we investigate the phenomena of electromagnetically induced transparency and the generation of second-order sideband in a Laguerre–Gaussian cavity optorotational system with a Kerr nonlinear medium. Using the perturbation method, we analyze the first- and second-order sideband generations in the output field from the system under the actions of a strong control field and a weak probe field. Numerical simulations show that the Kerr nonlinearity can lead to the occurrence of the asymmetric line shape in the transmission of the probe field. Comparing with traditional scheme for generating the second-order sideband, our spectral shape of the second-order sideband is amplified and becomes asymmetric, which has potential applications in precision measurement, high-sensitivity devices, and frequency conversion.
Parity-time (PT) symmetric systems, which rely on the balanced gain-loss condition and render the Hamiltonian non-Hermitian, have provided a new platform to engineer effective light-matter interactions in recent years. Here we explore the high-order sideband features of the output fields obtained from a PT-symmetric optical system consisting of a passive nonlinear cavity coupled to an active linear cavity. By employing a perturbation technique, we derive analytic formulas used to determine the nonlinear transmission coefficient of optical second-order sideband in this structure. Using experimentally achievable parameters, it is clearly shown that the efficiency of the second-order sideband generation can be greatly enhanced in the PT-symmetric dimer, extremely in the vicinity of the transition point from unbroken- to broken-PT regimes. Moreover, we further analyzed the influences of the system parameters, including the photon-tunneling rate between two cavities, Kerr nonlinearity strength, and optical detuning, on the second-order sideband generation. Subsequently we investigate the higher-order sideband output spectrum by numerical simulations, where the sideband amplitude also is largely enhanced in the PT-symmetric arrangement, compared with the passive-passive double-cavity system. Our obtained results provide a new avenue for acquiring optical high-order sidebands and operating light, which may inspire further applications in chip-scale optical communications and optical frequency combs.