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Electrically Controlled Dispersions of Nanoparticles for Reconfigurable Optical Lensing and Optical Cloaking Applications

 KSU.344

Abstract: The present invention relates to physics of metamaterials, describing a way to realize an electrically controlled optical medium with local refractive indices varying in space and/or time.  The medium is comprised of a dispersion of metallic particles of various shapes (rods) in various dielectric media (isotropic fluids, liquid crystals, polymers), whose position and orientation are controlled by an externally applied electric field.  By creating and controlling the spatial configuration of the refractive indices, one achieves various optical effects such as lensing and cloaking.  The developed material can bend light around a physical object, thus making it invisible/nearly invisible to an observer and shadow-less/nearly shadow-less.  The metamaterial is comprised of metal (gold, silver, etc.) nano-sized  particles of different shapes, such as rods; dispersed in a dielectric medium, for example fluids such as water, toluene, oil, glycerine, thermotropic liquid crystal (LC), lyotropic LC, polymer, elastomer, etc. Surface of the particles is functionalized to prevent their aggregation.  The material is controlled by applying electric field that aligns the metallic anisometric particles and also redistrubutes particles in space.  Both effects modify the local value of the dielectric permittivity of the composite metamaterial, thus modifying its effective optical refractive index (or indices, as the material is often birefringent).   The invention provides examples of configuration in which a dispersion of gold nanorods in fluids, controlled by an applied electric field, modifies the image of a thin (4 micrometers) metallic wire, causing it to disappear for a particular part of the optical spectrum and for a particular polarization.

Applications:

  •             Electrically-controlled lenses – and design of metamaterials with special properties
  •            Optical systems to achieve invisibility and shadowlessness – with or without highly-suppressed light scattering and diffraction

Advantages:

  •            New technique to make electrically reconfigurable optical elements like lenses and cloaks with refractive indices modified in space and time by applying electric field
  •           Chosen configuration of refractive indices can be frozen and made permanent  - for example by polymerization of the dispersive medium

 Inventors:  Dr. Oleg Lavrentovich and Dr. Andrii Golovin

Licensing Contact

Suguna Rachakonda

Associate Director, Technology Commercialization

Office: 330-672-3553  Fax: 330-672-7991

Email: srachako@kent.edu