Single-photon-level sub-Doppler pump-probe spectroscopy of rubidium

Paul Burdekin, Samuele Grandi, Rielly Newbold +3

We propose and demonstrate pump-probe spectroscopy of rubidium absorption which reveals the sub-Doppler hyperfine structure of the ${}^5$S${}_{1/2}\leftrightarrow$ ${}^5$P${}_{3/2}$ (…