Atomic Faraday beam splitter for light generated from pump-degenerate four-wave mixing in a hollow-core photonic crystal fiber

We demonstrate an atomic Faraday dichroic beam splitter suitable for spatially separating signal and idler fields from pump degenerate four-wave mixing in source. By rotating the plane of polarization one mode ${90}^{\ensuremath{\circ}}$ with respect to other, a subsequent polarizing separates two frequencies, which differ by only 13.6 GHz, achieves suppression $(\ensuremath{-}26.3\ifmmode\pm\else\textpm\fi{}0.1)$ $(\ensuremath{-}21.2\ifmmode\pm\else\textpm\fi{}0.1)$ dB outputs, corresponding transmission 97% 99%, respectively. This technique avoids necessity using spatial separation modes thus opens door enhancing process efficiency waveguide experiments. As proof principle, we generate light via $^{87}\mathrm{Rb}$ loaded into hollow-core photonic crystal fiber interface it splitter.