Hysteretic optomagnetic bistability based on the plasmon-induced inverse Faraday effect in magnetoplasmonic disk resonators

We investigate the inverse Faraday effect (IFE) by surface plasmon traveling modes in an ultracompact magnetoplasmonic disk resonator side-coupled to a plasmonic waveguide. The magnetic field by the IFE reacts to the traveling modes and leads to a nonlinear shift of the resonance in the disk resonator. Describing those nonlinear phenomena analytically by using the temporal coupled mode theory and the Lorentz reciprocity theorem, we propose a conception of hysteretic optomagnetic bistability that the system has two stable states of optically induced magnetic field to switch on and off, depending upon the history of the incident optical power. The numerical simulations agree well with the analytical prediction. The proposed conception may find potential applications in all-optical magnetic recording and switching with nanometer resolution.

Figure 1

The scheme of a magnetoplasmonic disk resonator coupled to a metal-insulator-metal waveguide. Here, ${\varepsilon }_r$ is the linear permittivity of the ferromagnetic dielectric, and $\alpha$ is the magneto-optical susceptibility.

Figure 2

Number of roots of Eq. (7) according to the normalized detuning $\mathrm{\Delta }$ and the incident power $P_{\mathrm{in}}$.

Figure 3

The effective magnetic field induced in the resonator according to the normalized detuning $\mathrm{\Delta }$ and the normalized waveguide powers $P_{\mathrm{in}}/P_{\mathrm{c}}$. (a) and (b) Analytical results from the roots of Eqs. (7) and (10). (c) and (d) Numerical simulation results compared with the above analytical results. (a) and (c) show the relation with the normalized detuning $\mathrm{\Delta }$ for different $P_{\mathrm{in}}/P_{\mathrm{c}}$. (b) and (d) show the relation with $P_{\mathrm{in}}/P_{\mathrm{c}}$ for different normalized detuning $\mathrm{\Delta }$.

Figure 4

Numerical simulation results of distributions of the effective magnetic field $H_{\mathrm{eff}}$ in the resonator for the case of Fig. 3.