Electro-Optic Effects in Colloidal Dispersion of Metal Nano-Rods in Dielectric Fluid

Andrii B Golovin; Jie Xiang; Heung-Shik Park; Luana Tortora; Yuriy A Nastishin; Sergij V Shiyanovskii; Oleg D Lavrentovich

doi:10.3390/ma4020390

Electro-Optic Effects in Colloidal Dispersion of Metal Nano-Rods in Dielectric Fluid

Materials (Basel). 2011 Feb 14;4(2):390-416. doi: 10.3390/ma4020390.

Authors

Andrii B Golovin¹, Jie Xiang^{2

3}, Heung-Shik Park^{4

5}, Luana Tortora⁶, Yuriy A Nastishin^{7

8}, Sergij V Shiyanovskii⁹, Oleg D Lavrentovich^{10

11}

Affiliations

¹ Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA. agolovin@kent.edu.
² Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA. jxiang@kent.edu.
³ Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH 44242, USA. jxiang@kent.edu.
⁴ Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA. hpark3@kent.edu.
⁵ Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH 44242, USA. hpark3@kent.edu.
⁶ Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA. ltortor1@kent.edu.
⁷ Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA. ynastish@kent.edu.
⁸ Institute of Physical Optics, 23 Dragomanov Str. Lviv, 79005, Ukraine. ynastish@kent.edu.
⁹ Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA. sshiyano@kent.edu.
¹⁰ Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA. olavrent@kent.edu.
¹¹ Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH 44242, USA. olavrent@kent.edu.

Abstract

In modern transformation optics, one explores metamaterials with properties that vary from point to point in space and time, suitable for application in devices such as an "optical invisibility cloak" and an "optical black hole". We propose an approach to construct spatially varying and switchable metamaterials that are based on colloidal dispersions of metal nano-rods (NRs) in dielectric fluids, in which dielectrophoretic forces, originating in the electric field gradients, create spatially varying configurations of aligned NRs. The electric field controls orientation and concentration of NRs and thus modulates the optical properties of the medium. Using gold (Au) NRs dispersed in toluene, we demonstrate electrically induced change in refractive index on the order of 0.1.

Keywords: dielectrophoretic effect; field induced birefringence; gold nano-rods; gradient of refractive index; liquid crystal formed by metal particles; optical cloak; optical metamaterial.