Research ArticlePHYSICS

A single-atom 3D sub-attonewton force sensor

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Science Advances  23 Mar 2018:
Vol. 4, no. 3, eaao4453
DOI: 10.1126/sciadv.aao4453
  • Fig. 1 Experimental configuration.

    An externally applied force (purple arrow) displaces a trapped 174Yb+ ion. The image formed by the phase Fresnel lens is shifted in two dimensions. Displacement along the focal axis alters the image spot size. For clarity, illustrated trap dimensions are not to scale. RF electrode needle spacing, 300 μm; lens focal length, 3 mm.

  • Fig. 2 Ion image.

    Wavelength-scale ion image with Gaussian fitting and FWHM sizes for the horizontal (H) and vertical (V) slices.

  • Fig. 3 Electrostatic force detection and ion movement in three axes.

    x and y axes refer to camera plane, and z axis refers to the optical axis of the imaging system. (A) Ion displacement and applied force as a function of the external voltage in the x axis. This axis corresponds to the orientation of the trapping needles and has the strongest confinement. (B) Same as (A) but for the y axis. The use of ranges in the force vertical axis of the plot represents the constrained systematic uncertainty due to unknown orientation of the trap principal axis with respect to our optical system. Error bars in (A) and (B) are smaller than the dots. (C) Same as (B) but for the z axis.

  • Fig. 4 Light force detection with a single ion.

    Ion displacement as a function of the light force (red dots) and linear fit to experimental data (blue line). The shaded region shows the 95% confidence level for linear fit to experimental data. Inset: Photons scattered by the ion as a function of the laser power. The green dashed line is the fitted curve from Eq. 1, scaled by the detection efficiency, used for calculating the saturation parameter s as a function of the laser power.

  • Table 1 Error budget.

    Average errors for the data points in Fig. 3.

    σfit (nm)
    σDRIFT(fit) (nm)1.1114.3
    σi,DRIFT(interpolation) (nm)2.49.912.7

Supplementary Materials

  • Supplementary Materials

    This PDF file includes:

    • section S1. Quantum limit
    • section S2. Constant mass assumption
    • section S3. Image spot width limitations
    • Reference (26)

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