Med støtte fra Forskningsstyrelsen (FNU) og Willum Kann Rasmussen Fonden
With the development of plasmonic-based nano-photonic devices Surface Plasmons have attracted the interest of the quantum optics community as well. Surface-Plasmon-Polaritons (SPPs) are combined oscillations of electrons together with electromagnetic waves at the interface between a metal and a dielectric that propagate parallel along this interface. Very recently it has been shown theoretically that these combined oscillations have unique properties and enable the coupling between single emitters and light fields, thus combining the fields of quantum optics and solid state physics. In our group we are investigating the quantum noise properties of SPPs by exciting them with nonclassical light fields. A part of the experimental setup, where we couple a laser field with high efficiency to a Surface Plasmon Polariton is shown in figure 1a and the picture in figure 1b shows a simulated Surface Plasmon Polariton mode as we are investigating with this setup. Right now we are generating non-classical SPPs by mean of squeezing their field amplitude below the shot noise limit.
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Figure 1: Close up view of a part of the experimental setup (a) and simulated Surface-Plasmon-Polariton (SPP) mode (b).
Strong coherent coupling between light and matter has been achieved in a number of physical systems, but the most successful approaches so far have employed atomic systems. In this project we want to pursue a novel route to strong coherent coupling of quantum systems based on solid-state technology. Using conducting nano-structures, enhanced coherent coupling between a nitrogen-vacancy (NV) center in a diamond nano-crystal and a surface plasmon can be achieved. This will allow us to construct a highly efficient device that emits single photons on demand, and to obtain strong nonlinearities at the level of single photons. The envisioned device is illustrated in the Figure.
a) b)
Figure: a) The diamond nanocrystal (green dipole) is optically excited and decays into the surface plasmon mode of the nanowire (gray wire). The plasmon is coupled to a nearby waveguide (dark blue waveguide) whereby a single photon can be coupled out in a well-defined direction (small arrow to the right). b) A weak optical field propagating in the waveguide is transferred to a surface Plasmon in the nanowire, where it interacts strongly with the diamond. The interaction leads to a nonlinearity that controls the propagation of the surface plasmon and produces state with non-classical behavior.
Ref.:
D.E. Chang, A.S. Sørensen, P. Hemmer and M. Lukin, Phys. Rev. Lett. 97, 0543002 (2006), Quantum optics with surface plasmons.
D.E. Chang, A. S. Sørensen, E.D. Demler and M.D. Lukin, Nature Physics 3, 807 (2007), A single-photon transistor using nanoscale surface plasmons.
In this project we are collaborating with the following groups: