Efficient interaction of light and matter at the ultimate limit of single photons and single emitters is of great interest from a fundamental point of view and for emerging applications in quantum engineering. However, the difficulty of generating single-photon streams with specific wavelengths, bandwidths, and power as well as the weak interaction probability of a single photon with an optical emitter pose a formidable challenge toward this goal. Here, we demonstrate a general approach based on the creation of single photons from a single emitter and their use for performing spectroscopy on a second emitter situated at a distance. While this first proof of principle realization uses organic molecules as emitters, the scheme is readily extendable to quantum dots and color centers. Our work ushers in a new line of experiments that provide access to the coherent and nonlinear couplings of few emitters and few propagating photons.

APS
doi.org/10.1103/physrevlett.108.093601
Phys.Rev.Lett.
Ultrafast Spectroscopy

Rezus, Y., Walt, S. G., Lettow, R., Renn, A., Zumofen, G., Götzinger, S., & Sandoghdar, V. (2012). Single-Photon Spectroscopy of a Single Molecule. Phys.Rev.Lett., 108(9), 093601: 1–5. doi:10.1103/physrevlett.108.093601