Polarization-selective quantum cooperative response in dual-species atom arrays

Abstract

Atom arrays have emerged as a powerful platform for quantum light-matter interfaces, yet single-species arrays are constrained by in-plane symmetry, restricting polarization control. Here we investigate the cooperative optical response of dual-species subwavelength atom arrays, in which intrinsic polarizability difference breaks in-plane symmetry. By engineering the lattice spacing and detunings, the arrays exhibit polarization-dependent subradiant modes, enabling complete reflection of specific polarization component. Leveraging this mechanism, we assemble array units as functional pixels and demonstrate a scalable polarization-selective quantum light modulator. Our work establishes a dynamically reconfigurable atomic-photonic platform for versatile subwavelength quantum optical elements.

Figures (5)

• Figure 1: (a) Array of two isotopic atomic species, with blue and red spheres denoting atoms of type A and B, respectively. (b) Corresponding two-level energy structure.
• Figure 2: Transmissions $T_x$ and $T_y$ as functions of lattice constant $a$. (a,b) The detuning is fixed at $\delta_A/\gamma = 1$, while $-\delta_B=1, 2, 5, 10, 100, \infty$. (c,d) The detuning is fixed at $\delta_B/\gamma = -1$, while $\delta_A=1, 2, 5, 10, 100, \infty$. Different curve colors denote different values of $\delta_A$ or $|\delta_B|$, as indicated in the legend of (a). Calculations assume an $N = 26 \times 26$ atom array and a diagonally polarized incident Gaussian beam with waist $w_0 = 0.3 \sqrt{N} a$.
• Figure 3: The transmissions and subradiant modes. (a, b) Transmissions $T_x$ and $T_y$ as functions of the lattice constant $a$. Colors represent $\delta/\gamma = 0.1, 0.3, 0.5, 0.7, 0.9$ (see legend in (a)). (c, d) Lattice constants yielding zero transmission versus detuning $\delta$, corresponding to $T_x$ and $T_y$, respectively. Blue solid and red dotted lines denote the first and second zeros (legend in (d)); The inset of (c) extends the results to a wider range of $\delta/\gamma$. The black straight line indicates the asymptotic scaling $a \sim \delta^{-0.32}$ at large $\delta$. Calculations assume the same atom array and incident beam as in Fig. \ref{['fig:TxTy_varyingdeltaAB']}.
• Figure 4: (a–c) Total light intensity and polarization distributions at propagation distances $z = 14\lambda$, $50\lambda$, and $90\lambda$, respectively. The color bar denotes the normalized optical intensity $I=(|E_x|^2+|E_y|^2)/|E_0|^2$, where $E_0$ is the peak amplitude of the incident Gaussian beam. White lines indicate the polarization distributions. Calculations assume $a/\lambda=0.4$ and $\delta/\gamma=0.5$. The figures span spatial ranges $x, y \in \left[-10 \lambda, 10 \lambda\right]$.
• Figure 5: (a) Patterned superarray with $2\times 2$ pixels, where each pixel is a dual-species stripe-pattern atom array. (b) Total light intensity and polarization distribution at $z=14\lambda$. Calculations assume an $N = 71 \times 71$ atom array with $a/\lambda=0.4$, and a diagonally polarized incident beam with waist $w_0 = 0.3 \sqrt{N} a$ and $\delta/\gamma=0.5$. Each pixel contains $30 \times 30$ atoms and the isolation width is $11$ lattice sites. The color bar denotes the normalized optical intensity $I=(|E_x|^2+|E_y|^2)/|E_0|^2$. White lines or ellipses indicate the polarization distribution.