Tunable quantum photonic routing using a coupled giant-atom-like array

Abstract

We examine a quantum routing mechanism utilizing a giant-atom-like array coupled to two one-dimensional waveguides. The giant-atom-like array is formed by a one-dimensional array of three-level-systems. In the regime of strong atom-waveguide coupling and weak inter-atomic interactions, this system functions as an efficient and directionally controllable single-photon router. Our analysis shows that the routing behavior is influenced by effective phase accumulation and interference effects, which can be adjusted by varying the number of coupling sites $N$, the photon energy $E$, and the inter-atomic coupling strength $J$. Importantly, we identify configurations that enable perfect photon transfer ($100 \%$ efficiency) over a wide range of energies and that provide dynamic control over the output channel. In addition, we investigate how the system responds to changes in its internal parameters, demonstrating the robustness and scalability of routing performance. These findings underscore the potential of this setup for implementation in reconfigurable and integrated quantum photonic networks.

Figures (7)

• Figure 1: Schematic representation of the physical system. (a) The upper panel illustrates the configuration of a coupled array of atoms that collectively behaves as a giant atom, interacting with two one-dimensional waveguides at spatially separated points. This configuration enables multi-path interference and non-local photon–atom coupling. (b) The lower panel shows a simplified schematic of the system, highlighting the effective giant-atom-like behavior arising from the spatially distributed coupling between the array and the two waveguides.
• Figure 2: Schematic representation of the virtual symmetric and antisymmetric channels for a giant-atom-like array. These channels are labeled with $+$ and $-$, respectively. The amplitudes of the transmission $t^{+}$ and $t^{-}$ and reflection $r^{+}$ are represented by orange wavy arrows.
• Figure 3: Transmission probability $T_A$ (solid red line), reflection $R_A$ (red dashed line), and transfer $T^{\rightarrow}_B$ (blue dotted-and-dashed line) and $T^{\leftarrow}_B$ (blue dotted line) spectra as a function of the incident energy $E$. The spectra are calculated for the parameters $\omega_0 = \omega_s = \omega_e = 0$, $\Omega = 0$, $J = 0.01$, and $g = 1.5$ (all units of $\xi$), for different numbers of atoms as indicated in the panels (a. 1)--(a. 4) and (b. 1)--(b. 4).
• Figure 4: Transmission probability $T_A$ (solid red line), reflection $R_A$ (red dashed line), and transfer $T^{\rightarrow}_B$ (blue dotted-and-dashed line) and $T^{\leftarrow}_B$ (blue dotted line) spectra as a function of the incident energy $E$. The spectra are calculated for the parameters $\omega_0 = \omega_s = \omega_e = 0$, $\Omega = 0$, $J = 0.01$, $g = 1.5$ (all units of $\xi$), and $k = \pi /2$.
• Figure 5: Density Probability transmission $T_A$ and transfer $T_B^{\rightarrow}$ spectra as a function of the incident energy $E$ and the number of atoms $N$. The spectra are calculated for the parameters $\omega_0 = \omega_s = \omega_e = 0$, $\Omega = 0$, $J = 0.01$, and $g = 1.5$ (all units of $\xi$).