Search

An adjustable unidirectional amplifier is proposed in a hybrid cavity magnonic system. By eliminating the rapidly dissipative auxiliary mode, we obtain the effective Hamiltonian for a typical three-body circulator. Through analyzing the transmission coefficients of the system, we find that the nonreciprocal transmission of photon–magnon as well as the amplification of arbitrary signals can be both realized without requiring in the parity-time symmetry condition. In addition, the amplification factor of our system is highly adjustable. Our theoretical scheme has potential implication in realizing magnonic triodes and magnon-based quantum information processing. • Adjustable nonreciprocal amplification between magneto-optical and photo-optical effects is achieved. • Unlike the amplification mechanisms in active devices (such as PT gain), we achieve amplification by constructing local gain within an overall passive device, introducing a novel concept of nonreciprocal amplification. • We provide an analytical solution for the amplification coefficient and explore the dependence of the amplification effect on various physical quantities. [ABSTRACT FROM AUTHOR]

Nonreciprocal transmission, reflection and absorption are very important in quantum science. For their realization, cavity magnonics is attracting much attention, where Kittel mode describing collective excitations of a large number of spins is excited through driving magnons with a strong microwave field. The cavity photons and magnons are coupled via magnetic dipole interaction, while the magnons and phonons are coupled via magnetostrictive interaction. By applying experimental feasible parameters, we breaks the symmetry of spatial inversion in order to realize nonreciprocal transmission, reflection absorption. Our results reveal a new strategy to protect quantum resources for building noise-tolerant quantum processors, realizing chiral networks, and invisible quantum sensing. • Nonreciprocal transmission, reflection and absorption are very important in quantum science. • In our schemes, cavity photons and magnons are coupled via magnetic dipole interaction, while the magnons and phonons are coupled via magnetostrictive interaction. By applying experimental feasible parameters, we breaks the symmetry of spatial inversion in order to realize nonreciprocal transmission, reflection absorption. • Our results reveal a new strategy to protect quantum resources for building noise-tolerant quantum processors, realizing chiral networks, and invisible quantum sensing. [ABSTRACT FROM AUTHOR]

• An all-optical diode device is proposed based on a topological photonic crystal heterostructure. • The heterostructure supports a tunable nonreciprocal topological edge mode with a perfect transmission. • The TES mode can be tuned by adjusting the incident angle of the input light in the linear regime. • The structure is used as a nonlinear all-optical diode by adjusting the intensity at a given angle of incidence. • The system acts as an all-optical diode in linear and nonlinear regimes. Here, we propose an all-optical diode device based on a topological photonic crystal heterostructure composed of two one-dimensional photonic crystals with a thin Weyl semimetal layer between them. An all-optical diode, a nonreciprocal device that allows perfect transmission in one direction and prohibits it in the opposite direction, is widely used in optical communication, all-optical signal processing, and information technology. The proposed structure can support a tunable nonreciprocal linear and nonlinear topological edge state with a perfect transmission. Unlike the photonic multilayer-based optical diodes, the proposed structure does not require strong nonlinearity and high spatial asymmetry. In the nonlinear regime, the transmission of the structure shows a bistable hysteresis loop with low switch-up and switch-down threshold intensities, which depend on the impinging direction of the input light. The topological edge state can be tuned by adjusting the incident angle of the input light in the linear regime. We can use the structure as a nonlinear all-optical diode by adjusting the intensity of the input beam at a given incident angle. [ABSTRACT FROM AUTHOR]

Highlights • A novel infrared nonreciprocal absorbers. • The optical properties of the CdTe magneto-optical material are investigated. • The Lorentz-Drude equations of dielectric constant tensor can predict the optical properties of CdTe well. • Obvious nonreciprocal effect can be achieved. • Important use for the infrared detector and infrared absorption regulation. Abstract In this paper, a novel CdTe gratings structure is designed aimed at constructing omnidirectional infrared nonreciprocal absorbers at wavelength from 18 μm to 23 μm. CdTe is a commonly used semiconductor infrared film material, which is widely used in photovoltaic, infrared detection, fluorescence and other applications. The optical radiation characteristics of magneto-optical material CdTe are studied based on the Lorentz-Drude model, which is verified with the optical constants in handbook. The time-domain finite difference (FDTD) method was used to calculate the infrared radiation characteristics of CdTe gratings, and the electric field square modulus distribution with different wavelengths is presented. It is found that the nonreciprocal absorptivity is obvious as the incidence angle is 45° at the positive and negative angles. The effects of magnetic field strength, grating thickness, incidence angles on the optical properties, especially the non-reciprocity are analyzed in details. The numerical simulation results are useful to the thermal radiative design in infrared absorber and other optical instrument. [ABSTRACT FROM AUTHOR]

By employing classic electromagnetic theory, we have theoretically investigated the properties of lateral shift (LS) in the interface between air and the gyrotropic medium (gyroelectric medium and gyromagnetic medium). The influence of the electromagnetic (EM) parameters, incident angle and thickness of the plate on the shift have also been analyzed. Due to the gyrotropic element of EM parameters, the numerical results have shown that the LS is nonreciprocal with the incident angle, EM parameters and thickness of the plate. [ABSTRACT FROM AUTHOR]

Compared with reciprocal optical materials, nonreciprocal materials can break the time reversal and detailed balance due to special nonreciprocal effect, while how its characteristics performing on infrared wavelength have not been paid enough attention. In this paper, the optical properties of three magneto-optical materials was investigated in infrared band, that are n-InAs, GaAs, HgCdTe, based on Finite Difference Time Domain (FDTD) method. The equations of dielectric constant tensor are present and the effect of magnetic field intensity and frequency has been studied in detail. Additionally, the effect of incidence angle at positive and negative directions to the nonreciprocal absorptivity is also investigated. It is found that the nonreciprocal effect is obvious in infrared wavelength, and the nonreciprocal effect could adjust the absorption characteristic, thus be able to tune the absorption for the specific frequency of incident light. In addition to modeling the directional radiative properties at various angles of incidence, the absorption peaks of three materials under different incident angles are also calculated to understand the light absorption and to facilitate the optimal design of high-performance photovoltaic and optical instrument. [ABSTRACT FROM AUTHOR]

• The electrical conductivities and dielectric constants of graphene based on different theoretical models are discussed. • A novel magneto-plasma structure has been proposed for achieving high absorptivity. • The non-reciprocal optical properties effect has been enhanced. • The physical mechanisms of the enhancement for nonreciprocal effect are discussed. • The model is useful for design and application in nonreciprocal optical devices. We present a theoretical study of the magnetic field dependence of the nonreciprocal absorption effect for composite microstructure. We analyses and summarizes the relevant conductivity calculation models of graphene, and discusses and compares the electrical conductivities and dielectric constants of graphene based on different theoretical models. Moreover, the external magnetic field applied model and the non-magnetic field applied model are compared in details, the most suitable calculation model has finally chosen. And the influence of the chemical potential on the refractive index of graphene was compared and discussed under the condition of an external magnetic field. Furthermore, we propose a nonreciprocal effect enhanced magneto-optical composite microstructure using graphene and analyze the effect of grating height, grating filling ratio, incidence angle and magnetic field intensity on the nonreciprocal absorptance, in this work. It is found that graphene can effectively enhance the nonreciprocity phenomenon in the wavelength range, and the absorptance can also be greatly improved. [ABSTRACT FROM AUTHOR]