Gain-assisted control of the photonic spin Hall effect

TL;DR

This paper presents a gain-assisted method to control the photonic spin Hall effect using a cavity with a three-level atomic medium, enabling switchable spin accumulations and potential applications in optical sensing.

Contribution

It introduces a novel gain-assisted model for controlling the photonic SHE in atomic media, allowing tunable spin accumulation directions and magnitudes.

Findings

Switchable spin accumulation direction across the Brewster angle.

Higher peak SHE in anomalous dispersion compared to normal dispersion.

Control of SHE magnitude and angular range via Rabi frequencies and detuning.

Abstract

In the photonic spin Hall effect (SHE), also known as the transverse shift, incident light photons with opposite spins are spatially separated in the transverse direction due to the spin-orbit interaction of light. Here, we propose a gain-assisted model to control the SHE in the reflected probe light. In this model, a probe light is incident on a cavity containing a three-level dilute gaseous atomic medium, where the interaction between the atom and the control field follows two-photon Raman transitions. We show that the direction of photonic spin accumulations can be switched between positive and negative values across the Brewster angle in both the anomalous and normal dispersion regimes. For the same magnitude of control fields, the peak value of the photonic SHE is higher in the anomalous dispersion region compared to the normal dispersion regime. Additionally, the angular range around the Brewster angle is wider in the normal dispersion regime than in the anomalous dispersion region. Furthermore, the peak value of the photonic SHE and the angular range can be controlled by changing the Rabi frequencies of the control fields and the probe field detuning. The measurement of photonic SHE based on gain assistance may enable spin-related applications such as optical sensing.