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

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 δ+h≈−3300λ 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 δ+h≈4000λ. 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.