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Tunable optical forces between nanophotonic waveguides


The confinement of light in components with nanoscale cross-sections in nanophotonic circuits significantly enhances the magnitude of the optical forces experienced by these components1,2. Here we demonstrate optical gradient forces between two nanophotonic waveguides, and show that the sign of the force can be tuned from attractive to repulsive by controlling the relative phase of the optical fields injected into the waveguides. The optical gradient force could have applications in optically tunable microphotonic devices and nanomechanical systems.

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Figure 1: The Mach–Zehnder interferometer.
Figure 2: Force (calculated) versus distance for different relative mode excitations.
Figure 3: Calibration, transmission and transduction.
Figure 4: The experimental setup.
Figure 5: Determining the optical force.


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The authors thank the Research Foundation—Flanders (FWO) for financial support. We also thank L. Haentjes for help with the construction of the vacuum chamber, M. Verbist for taking the SEM image, W. Bogaerts for help with the design of the waveguides and S. Verstuyft for help with processing.

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Authors and Affiliations



J.R. and I.D.V. conceived and designed the experiments. J.R. performed the experiments, analysed the data and wrote the paper. J.R. and B.M. performed numerical simulations. L.L., D.V.T. and R.B. contributed materials and analysis tools. All authors discussed the results and provided feedback and comments on the manuscript.

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Correspondence to Joris Roels.

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Roels, J., De Vlaminck, I., Lagae, L. et al. Tunable optical forces between nanophotonic waveguides. Nature Nanotech 4, 510–513 (2009).

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