We demonstrate state detection based on coherent Raman repumping and a two-color Raman state transfer. The Raman coupling during detection selectively eliminates unwanted dark states in the fluorescence cycle without compromising the immunity of the desired dark state to off-resonant scattering. We demonstrate this technique using 137Ba+ where a combination of Raman coupling and optical pumping leaves the D3/2∣F"=3,mF"=3⟩ metastable state optically dark and immune to off-resonant scattering. All other states are strongly coupled to the upper P1/2 levels. We achieve a single shot state-detection efficiency of 89.6(3) in a 1ms integration time, limited almost entirely by technical imperfections. Shelving to the ∣F"=3,mF"=3⟩ state before detection is performed via a two-color Raman transfer with a fidelity of 1.00(3).
@article{arxiv.1105.0763,
title = {State detection using coherent Raman repumping and two-color Raman transfers},
author = {Boon Leng Chuah and Nick C. Lewty and Murray D. Barrett},
journal= {arXiv preprint arXiv:1105.0763},
year = {2011}
}