Microwave control of photonic spin Hall effect in atomic system

TL;DR

This paper theoretically demonstrates how microwave fields can control the photonic Spin Hall Effect in atomic systems, enabling tunable polarization shifts and potential applications in quantum sensing and optical switching.

Contribution

It introduces a method to control the photonic SHE via microwave fields and phase tuning in a closed-loop atomic system, which was not previously explored.

Findings

Photonic SHE magnitude can be maximized at zero detuning and specific phase conditions.

Angular position of SHE shifts linearly with microwave coupling strength.

Microwave-controlled switching of SHE is achievable by phase tuning.

Abstract

The photonic Spin Hall Effect (SHE) causes a polarization-dependent transverse shift of light at an interface. There is a significant research interest in controlling and enhancing the photonic SHE. In this paper, we theoretically investigate the microwave field control of the photonic SHE in a closed-loop $\Lambda$-type atomic system. We demonstrate that both the magnitude and angular position of the photonic SHE can be controlled by varying the relative phase $\phi$ between the driving optical fields and the strength of the microwave coupling $\Omega_{\mu}$. At zero probe field detuning ($\Delta_p = 0$) and $\phi=0,\pi$, the photonic SHE magnitude reaches to upper limit equal to the half of the incident beam waist, and remains largely unaffected by the microwave strength $\Omega_{\mu}$, but its angular position shifts linearly with increasing $\Omega_{\mu}$. At intermediate phases, especially at $\phi = \pi/2$, the magnitude of the photonic SHE exponentially decreases with the increase of $\Omega_{\mu}$. Interestingly, we observed microwave-controlled switching of photonic SHE by tuning the relative phase $\phi$ at an optimized value of $\Omega_{\mu}$ and $\Omega_{c}$. In contrast, at $\Delta_p = \pm \Omega_c$, a maximum photonic SHE equal to half of the incident beam waist occurs at $\phi \leq \pi$ and $\Omega_{\mu} \geq \Omega_p$, where both real and imaginary parts of the susceptibility vanish, yielding a unit refractive index. Our results may have potential applications in microwave quantum sensing and quantum optical switches based on the photonic SHE.