Few-photon coherent nonlinear optics with a single molecule


The pioneering experiments in linear spectroscopy were performed using flames in the 1800s, but nonlinear optical measurements had to wait until lasers became available in the twentieth century. Because the nonlinear cross-section of materials is very small1,2, macroscopic bulk samples and pulsed lasers are usually used. Numerous efforts have explored coherent nonlinear signal generation from individual nanoparticles3,4,5 or small atomic ensembles6,7,8 with millions of atoms. Experiments on a single semiconductor quantum dot have also been reported, albeit with a very small yield9. Here, we report the coherent nonlinear spectroscopy of a single molecule under continuous-wave single-pass illumination and the switching of a laser beam by on the order of ten pump photons. The sharp molecular transitions and efficient photon–molecule coupling at a tight focus10 allow for optical switching with less than a handful of pump photons and are thus promising for applications in quantum engineering11.

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Figure 1: Experimental set-up.
Figure 2: Resonant and near-resonant pump–probe spectroscopy.
Figure 3: Four-wave mixing.
Figure 4: Time-domain measurements.
Figure 5: Few-photon switching.


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This work was financed by the Max Planck Society, an Alexander von Humboldt professorship and the European Research Council Advanced Grant (SINGLEION). We acknowledge helpful discussions with D. Martin-Cano. V.S. thanks B. Lounis for fruitful discussions in the very early stages of this work.

Author information

A.M. and B.G. performed the experiments and analysed the data. V.S. conceived the project. V.S., S.G. and T.U. supervised the experiments. All authors discussed the results. A.M., B.G. and V.S. wrote the manuscript.

Correspondence to Vahid Sandoghdar.

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Maser, A., Gmeiner, B., Utikal, T. et al. Few-photon coherent nonlinear optics with a single molecule. Nature Photon 10, 450–453 (2016). https://doi.org/10.1038/nphoton.2016.63

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