Plasmono-Atomic Interactions on a Fiber Tip

Light-atom interaction can be engineered by interfacing atoms with various specially designed media and optical fibers are convenient platforms for realization of compact interfaces. Here, we show that an optical fiber sensor bearing a plasmonic metasurface at its tip can be used to detect modifications of the Doppler-free hyperfine atomic spectra induced by coupling between atomic and plasmonic excitations. We observed the inversion of the phase modulation reflectivity spectra of Cesium vapor in presence of the metamaterial. This work paves the way for future compact hybrid atomic devices with a cleaved tip as substrate platform to host various two-dimensional materials.