Robust Universal Photon Blockade in a Bimodal Jaynes-Cummings Model via Kerr Nonlinearity

Abstract

Universal photon blockade in a two-mode Jaynes-Cummings model incorporating third-order Kerr nonlinearity is demonstrated with a single two-level atom coupled to a waveguide microcavity. Realization of this universal photon blockade is attributed to the cooperative effects of field-atom coupling and Kerr nonlinearity. More importantly, this antibunching is found to be robust against the atomic spontaneous emission, driving field strength, and defect-induced cavity mode coupling. The strong antibunching effect in this resonance-driven scheme is essentially different from those without Kerr nonlinearity. Moreover, this work expands the platform for achieving universal photon blockade and reveals the cooperative advantages of nonlinearities in enhancing the purity and brightness of single-photon sources, representing a novel strategy toward high-performance single-photon sources in integrated quantum optical devices.

Figures (9)

• Figure 1: Schematic of a microcavity coupled to a single two-level atomic system. The cavity's CW mode is driven by a tapered fiber waveguide, where $\kappa_{ex}$ is the coupling rate between the waveguide and the microcavity. The WGM microcavity supports two optical modes: a clockwise (CW) propagation mode and a counterclockwise (CCW) propagation mode (indicated by red and blue arrows, respectively), each exhibiting Kerr nonlinearity. Both modes within the cavity are simultaneously coupled to a single two-level atom with the coupling strength g. The intrinsic decay rate of the microcavity is $\kappa_{i}$, and the spontaneous emission rate of the atom is $\gamma$
• Figure 2: Comparison of the dressed state energy levels for systems with no Kerr nonlinearity (left) and strong Kerr nonlinearity (right) under strong coupling. Three energy levels exist under single excitation, while five levels exist under double excitation.
• Figure 3: Schematic diagram of the dressed-state energy level structure of the system in the two-photon excitation subspace as functions of the cavity-atom coupling strength $g$ and the Kerr nonlinearity $\chi$. The black dot-dashed line marks the position of the two-excitation energy level on resonance with the single-excitation frequency, while the orange dashed line indicates the energy level at $2(\omega+\chi)$. (a) Under resonant driving, the anharmonicity of the energy levels at zero detuning becomes more pronounced as the cavity-atom coupling strengthens ($\chi=8$). (b) When the cavity-atom coupling is strong, the anharmonicity of the energy levels gradually increases with the enhancement of the Kerr nonlinearity ($g=10$)
• Figure 4: The energy level diagram of the driven CW propagating cavity mode in the WGM within the few-photon subspace. Destructive interference between these paths prevents two photons from occupying the same energy level, leading to UPB.
• Figure 5: Comparison of numerical and analytical results of the second-order correlation function and the probability amplitudes of photon excitations with and without Kerr nonlinearity (The subscripts “N” and “A” denote “Numerical” and “Analytical”, respectively). (a) Steady-state second-order correlation function $g^{(2)}(0)$ vs. detuning $\Delta/\kappa$. (b) Variations in $P(1)$ and $P(2)$ with detuning. The location of CPB coincides with the maximum value of $P(1)$, while the location of UPB corresponds to the minimum value of $P(2)$. Other parameters: $g/\kappa=1.33$, $\Omega/\kappa=0.1$, $\chi/\kappa=8$, $\gamma=\kappa$.