Research ArticleQUANTUM OPTICS

Single-plasmon interferences

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Science Advances  11 Mar 2016:
Vol. 2, no. 3, e1501574
DOI: 10.1126/sciadv.1501574
  • Fig. 1 The plasmonic platform.

    (A) Scanning electron microscope top view of the photon-to-SPP launcher. It is made of 11 grooves of asymmetric dimensions (29). (B) Scanning electron microscope top view of the plasmonic chip. Striped rectangles 1 and 2 are the SPP launchers as shown in (A). The groove doublet forms a plasmonic BS. The characterized splitter gives T1 = 29 ± 1% and R1 = 18 ± 1% when shining from coupler 1 and T2 = 32 ± 1% and R2 = 15 ± 1% when shining from coupler 2. For both input ports, the losses of the BS are measured to be approximately 53%. The SPPs propagate from launcher 1 or 2 to the BS and finally reach the large slits (black rectangles) where they are converted into photons in the silica substrate. (C) Line shape of the sample. It exhibits how an SPP can be generated with a Gaussian beam focused orthogonally to the photon-to-SPP converter. The SPP reaches the grooves of the plasmonic BS and finally propagates to the slit. The slit allows the SPP to couple out as photon in the substrate at 42° with an efficiency of about 50%.

  • Fig. 2 Experiments on SSPs showing the unicity of the SPP state and its wave behavior.

    (A) Sketch of the SPP experiments. The orientation of the first half-wave plate (HWP0) determines the polarization state impinging on the PBS cube and allows choosing between the HBT and MZ configurations of the SPP setup. HWP1 and HWP2 are half-wave plates that control the polarization of the incident beams on the photon-to-SPP couplers. For both experiments, we recorded the heralding rate RC and the heralded rates RA|C, RB|C, and RAB|C. (B) Intensity correlation function at zero delay g(2)(0) as a function of the mean photon number produced in the gating window ΔT = 10 ns. The lowest measured value of g(2)(0) obtained is 0.03 ± 0.06, which is well below the classical limit and is a signature of a single SPP state. The data points were obtained with 20 min of integration. (C) The single SPP source was used at g(2)(0) = 0.25 to perform interferences in an MZ interferometer for SPPs. We plotted the heralded photon output rates RA|C (red circles) and RB|C (blue squares) of the MZ interferometer for a varying delay in one arm of the interferometer. The solid lines are the sine fit functions of our experimental data.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/2/3/e1501574/DC1

    Section S1. Characterization of the single-photon source.

    Section S2. Characterization of the plasmonic chip.

    Section S3. Fit function for HBT experiments.

    Section S4. The lossy BS influence on the MZ interferences.

    Fig. S1. Single-photon source antibunching.

    Fig. S2. Schematic of the lossless-lossy MZ interferometer.

    Fig. S3. Reflection and transmission coefficients of the plasmonic BS as a function of the incidence angle.

    Fig. S4. Comparison between experimental data and numerical simulation of the plasmonic MZ outputs.

    References (32, 33)

  • Supplementary Materials

    This PDF file includes:

    • Section S1. Characterization of the single-photon source.
    • Section S2. Characterization of the plasmonic chip.
    • Section S3. Fit function for HBT experiments.
    • Section S4. The lossy BS influence on the MZ interferences.
    • Fig. S1. Single-photon source antibunching.
    • Fig. S2. Schematic of the lossless-lossy MZ interferometer.
    • Fig. S3. Reflection and transmission coefficients of the plasmonic BS as a function of the incidence angle.
    • Fig. S4. Comparison between experimental data and numerical simulation of the plasmonic MZ outputs.
    • References (32, 33)

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