Large-area flexible 3D optical negative index metamaterial formed by nanotransfer printing

Journal name:
Nature Nanotechnology
Year published:
Published online


Negative-index metamaterials (NIMs) are engineered structures with optical properties that cannot be obtained in naturally occurring materials1, 2, 3. Recent work has demonstrated that focused ion beam4 and layer-by-layer electron-beam lithography5 can be used to pattern the necessary nanoscale features over small areas (hundreds of µm2) for metamaterials with three-dimensional layouts and interesting characteristics, including negative-index behaviour in the optical regime. A key challenge is in the fabrication of such three-dimensional NIMs with sizes and at throughputs necessary for many realistic applications (including lenses, resonators and other photonic components6, 7, 8). We report a simple printing approach capable of forming large-area, high-quality NIMs with three-dimensional, multilayer formats. Here, a silicon wafer with deep, nanoscale patterns of surface relief serves as a reusable stamp. Blanket deposition of alternating layers of silver and magnesium fluoride onto such a stamp represents a process for ‘inking’ it with thick, multilayer assemblies. Transfer printing this ink material onto rigid or flexible substrates completes the fabrication in a high-throughput manner. Experimental measurements and simulation results show that macroscale, three-dimensional NIMs (>75 cm2) nano-manufactured in this way exhibit a strong, negative index of refraction in the near-infrared spectral range, with excellent figures of merit.

At a glance


  1. Fabricating 3D NIMs by transfer printing.
    Figure 1: Fabricating 3D NIMs by transfer printing.

    a, Schematic of steps for printing. b, Top-view SEM image of a silicon stamp (left; inset, magnified view), tilted view (52°) SEM image of a stack of alternating layers of Ag and MgF2 on a silicon stamp (middle; inset, magnified top view), cross-sectioned by FIB, and a macroscopic optical image of a large (~2.5 × 2.5 cm) printed 3D NIM (right). c, Corresponding SEM images of a tilted silicon stamp (left), an eleven-layer Ag/MgF2 stack (middle) and a printed 3D NIM (right: inset, magnified top view). Period P of the structure is 850 nm, and the depth-averaged widths of the ribs in the fishnet along the x- and y-directions are 635 nm (Wx) and 225 nm (Wy), respectively. The thicknesses of the Ag and MgF2 layers are 30 and 50 nm, respectively.

  2. Large-area, printed 3D NIMs in supported and free-standing configurations.
    Figure 2: Large-area, printed 3D NIMs in supported and free-standing configurations.

    a, Large-area SEM image of a representative region of a printed 3D NIM. b,c, SEM images of cross-sectional (FIB milled) and top views of this structure. d, SEM image of a flexible 3D NIM membrane formed by release and subsequent deposition on a solid support.

  3. Macroscale, printed 3D NIMs and demonstration of use in a repetitive /`manufacturing/' mode.
    Figure 3: Macroscale, printed 3D NIMs and demonstration of use in a repetitive ‘manufacturing’ mode.

    a, Macroscopic optical image of a 10 cm × 10 cm multilayer deposit on a large-area silicon stamp. b, 3D NIM printed with such a stamp onto a flexible substrate, in a single step. c, Tilted view (~15°) macroscopic optical images of three different 3D NIMs printed using a single stamp. d, Corresponding representative small-area SEM views of these three samples.

  4. Experimental measurements and simulation results for transmission/reflection and refractive indices of 3D NIMs.
    Figure 4: Experimental measurements and simulation results for transmission/reflection and refractive indices of 3D NIMs.

    a,b, Experimental and FDTD results for transmission (T) and reflection (R) spectra of a three-layer NIM monolayer (a) and an eleven-layer 3D NIM (b). c, Transmission spectra collected from five different locations across the entire area of a 8.7 cm × 8.7 cm, eleven-layer 3D NIM. d, Corresponding retrieved indices for three and eleven layers showing a negative index of refraction in the NIR band. e, FOM of three- and eleven-layer 3D NIM structures. f, The 4.48° NIM prism showing negative-phase propagation at λ = 1.95 µm. In all cases, P = 850 nm, depth-averaged Wx = 635 nm and Wy = 225 nm, Ag thickness = 30 nm, MgF2 thickness = 50 nm, and background refractive index ns = 1.2.


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Author information


  1. Departments of Materials Science and Engineering, Beckman Institute, and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA

    • Debashis Chanda,
    • Kazuki Shigeta,
    • Sidhartha Gupta,
    • Tyler Cain,
    • Andrew Carlson,
    • Agustin Mihi,
    • Paul Braun &
    • John A. Rogers
  2. Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA

    • John A. Rogers
  3. US Navy NAVAIR-NAWCWD, Research and Intelligence Department, Chemistry Branch, China Lake, California 93555, USA

    • Alfred J. Baca
  4. Sandia National Laboratories, Albuquerque, New Mexico, USA

    • Gregory R. Bogart


D.C. conceived the idea and designed experiments. J.A.R. provided technical guidance. D.C., K.S. and T.C. performed the experiments. D.C. measured, analysed and simulated the data. G.R.B., S.G., A.M., A.C., A.B. and P.B. contributed materials and analysis tools. D.C. and J.A.R. co-wrote the paper.

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The authors declare no competing financial interests.

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