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 an atomic source. By rotating the plane of polarization of one mode 90∘ with respect to the other, a subsequent polarizing beam splitter separates the two frequencies, which differ by only 13.6 GHz, and achieves a suppression of (‒26.3 ±0.1 ) and (‒21.2 ±0.1 ) dB in the two outputs, with a corresponding transmission of 97% and 99%, respectively. This technique avoids the necessity of using spatial separation of four-wave mixing modes and thus opens the door for enhancing the process efficiency in waveguide experiments. As a proof of principle, we generate light via four-wave mixing in 87Rb loaded into a hollow-core photonic crystal fiber and interface it with the atomic Faraday dichroic beam splitter.