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Los Alamos National LaboratoryCenter for Integrated Nanotechnologies
Helping you understand, create, and characterize nanomaterials

2020 Highlights

A selection of CINT science highlights from staff and user research.

CINT Contacts  

  • Abul Azad
  • Nanophotonics and Optical Nanomaterials Thrust
  • Email
  • Hou-Tong Chen
  • Nanophotonics and Optical Nanomaterials Thrust
  • Email

Nonreciprocity Enables Next-Generation Communication Technology

Scientific Achievement

For the first time, scientists have demonstrated extreme nonreciprocity in microwave reflections, allowing one-way steering and focusing of signals.

Significance and Impact

Electronically-controlled 2D metasurfaces could optimize next-generation communications through efficient microwave communications, one-way microwave mirrors, beam steering without moving pieces, and optical isolation.

Research Details

The image shows a schematic of focusing for microwave radiation.
  • A dynamic metasurface with reduced size, weight, and power was designed using conventional circuit board materials and varactors, which provide variable capacitance.
  • By modulating the metasurface in time and space, Lorentz reciprocity is broken, resulting in nonreciprocal scattering.
  • Non-reciprocal effects were experimentally achieved both in 1D (steering) and in 2D (focusing) for microwave radiation.
  • The image shows a schematic of one-way focusing. The forward reflection is focused to a point; the reverse process yields surface waves. Most reflectors are reciprocal. In the case of a bathroom mirror, if you can see someone reflected in it, they can see you too. A nonreciprocal mirror would enable you to see someone without them seeing you.

Publication: Cardin AE, Silva SR, Vardeny SR, Padilla WJ, Saxena A, Taylor AJ, Kort-Kamp WJ, Chen HT, Dalvit DA, Azad AK. Surface-wave-assisted nonreciprocity in spatio-temporally modulated metasurfaces. Nature Communications. 2020 Mar 19;11(1):1-9. [DOI: 10.1038/s41467-020-15273-1]

Funding: We are grateful to the ISR Fab-Lab at LANL for mounting the varactors on the metasurface. D.D. thanks Lukasz Cincio for computational assistance. Research presented in this paper was supported by the Laboratory Directed Research and Development program of Los Alamos National Laboratory under project number 20180062DR. Part of this work was performed at the Center for Integrated Nanotechnologies, a U.S. Department of Energy, Office of Basic Energy Sciences user facility. LANL is operated by Triad National Security, LLC, for the National Nuclear Security Administration of the U.S. Department of Energy (Contract No. 89233218CNA000001).

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