Chiral light–matter interactions in hot vapor-cladded waveguides

Recently, there has been growing interest in integrating alkali vapors with nanoscale photonic structures, such as nanowaveguides, resonators, and nanoantennas. Nanoscale confinement of electromagnetic fields may introduce a longitudinal electric field component, giving rise to circularly polarized modes that are essential for diverse applications involving vapor and light, such as chirality and nonreciproc-ity. Hereby, we have designed, fabricated, and characterized a miniaturized vapor cell that is integrated with optical waveguides that are designed to generate a peculiar circular-like polarization. Taking advantage of this phenomenon, we demonstrate a spectral shift in the atomic absorption signatures at varying magnetic fields, and significant isolation between forward-and backward-propagating waves in our atomic-cladded waveguide. Our results pave the way for the utilization of chip-scale integrated atomic devices in applications such as optical isolation and high spatial resolution magne-tometry.