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Silicon nanostructure cloak operating at optical frequencies


The ability to render objects invisible using a cloak (such that they are not detectable by an external observer) has long been a tantalizing goal1,2,3,4,5,6. Here, we demonstrate a cloak operating in the near infrared at a wavelength of 1,550 nm. The cloak conceals a deformation on a flat reflecting surface, under which an object can be hidden. The device has an area of 225 µm2 and hides a region of 1.6 µm2. It is composed of nanometre-size silicon structures with spatially varying densities across the cloak. The density variation is defined using transformation optics to define the effective index distribution of the cloak.

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Figure 1: Cloaking principle of the fabricated device.
Figure 2: Scanning electron microscope images of the cloaking device.
Figure 3: Two-dimensional spatial effective refractive index distribution of the cloaking device.
Figure 4: Simulations of the cloaking device.
Figure 5: Output images from the fabricated devices, tested by launching light with a wavelength of 1,550 nm into the waveguide and imaging the edge of the device (dashed lines).


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The authors would like to acknowledge the support of Cornell's Center for Nanoscale Systems (CNS), funded by the National Science Foundation. This work was performed in part at the Cornell Nanoscale Facility, a member of the National Nanotechnology Infrastructure Network, which is supported by the National Science Foundation.

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Authors and Affiliations



L.H.G. designed and simulated the devices. L.H.G. and J.C. carried out the fabrication of the samples. L.H.G. and C.B.P. conducted the experiments. L.H.G., C.B.P. and M.L. designed the experiments and discussed their results and implications.

Corresponding author

Correspondence to Michal Lipson.

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Gabrielli, L., Cardenas, J., Poitras, C. et al. Silicon nanostructure cloak operating at optical frequencies. Nature Photon 3, 461–463 (2009).

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