Harnessing Doppler broadening for giant photonic spin Hall shifts in an atomic cavity

Abstract

We investigate the horizontal and vertical polarized photonic spin Hall effect (PSHE) in an optical cavity having a three-level atomic medium under electromagnetically induced transparency (EIT). Both the absence and presence of Doppler broadening effect (DBE) are analyzed, revealing that DBE plays a crucial role in significantly enhancing the PSHE. Remarkably, the horizontal PSHE reaches values as large as ${\delta }_{+}^h\approx -3300\lambda$ under DBE. Furthermore, we systematically examine the impact of gain and loss in the cavity walls in the presence of DBE. Our results show that a balanced gain–loss configuration gives rise to an even greater enhancement, achieving ${\delta }_{+}^h\approx 4000\lambda$. The vertical polarized PSHE also exhibits substantial amplification under the combined influence of DBE and balanced gain–loss conditions. These findings provide new insights into tailoring spin-dependent light–matter interactions and offer a promising route for designing advanced photonic devices with controllable spin Hall shifts.