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A photoconductive approach to negative refraction

Krzysztof P. Orliński 1Maria Massaouti 2Maria Kafesaki 2Stelios Tzortzakis 2Dorota A. Pawlak 1

1. Institute of Electronic Materials Technology (ITME), Wólczyńska 133, Warszawa 01-919, Poland
2. Institute of Electronic Structure and Laser, FORTH,, P.O. Box 1527, Vassilika Vouton, Heraklion 71110, Greece


   Almost half a century has passed since Victor Veselago published his work [1] on negative refractive index. The idea grew, following the experiments of Smith [2], Hoffman [3], Yao [4] and many more to establish the field of optical metamaterials. Negative refractive index was originally demonstrated on various metallodielectric materials, such as split-ring resonators [5], pairs of metallic wires, or a fishnet structure. Only later negative refraction has been demonstrated in the materials with hyperbolic dispersion, which are structurally anisotropic materials with anisotropic distribution of permittivity,e.g. silver rods embedded in alumina matrix4. Directional solidification of eutectics provides possibilities of manufacturing materials with various geometries such unusual as split-rings [6] as well as so usual as rods of one phases embedded in another phase [7]. That is why in this paper we will utilize the eutectic materials.

   We propose a different approach to manufacturing a switchable metamaterial, suggested by S. Tzortzakis. A fibrous structure in the form of a ceramic eutectic is composed of two materials, each with a different bandgap. The matrix material is chosen as to have a big energy bandgap (e.g. 5eV), whereas the fibre material should have at least 2eV lowerbandgap. The idea is to transform the rods into the conductive state with a strong laser pulse. That way the material can be switched “on” and “off” according to the will of the user.

   We present results obtained for a GdCrO3-Gd2O3 eutectic fabricated by the micro-pulling down method. The single phase materials were synthesized in the form of powders via sol-gel combustion method. The THz time-domain spectroscopy was performed on all three types of samples and dielectric permittivitiesof the component phases (GdCrO3, Gd2O3) were utilized to perform the modeling of the electromagnetic properties of the eutectic composite.The first results reveal resonant

[1] „The electrodynamics of substances with simultaneously negative values of ε and μ” – Veselago V., Soviet Physics USPEKHI 10 (509) 1968

[2] “Composite Medium with Simultaneously Negative Permeability and Permittivity” - Smith, D. R.; Padilla, WJ; Vier, DC; Nemat-Nasser, SC; Schultz, S.; Physical Review Letters 84 (18) 2000, pp. 1484-1487

[3] „Negative refraction in semiconductor metamaterials” – Hoffman, A. J.; Alekseyev, L.; Howard, S. S.; Franz, K. J.; Wasserman, D.; Podolskiy, V. A.; Narimanov, E. E.; Sivco, D. L.; Gmachl, C.; Nature Materials 6, 2007

[4] „Optical negative refraction in bulk metamaterials of nanowires” – Yao, J.; Liu, Zh.; Liu, Y.; Wang, Y.; Sun, Ch.; Bartal, G.; Stacy, A. M.; Zhang, X.; Science 321, 2008

[5] „Reversing light: Negative refraction” – Smith, D.R., Pendry, J.B.; Physics Today 57(6) 2003

[6] “How far are we from making metamaterials by self-organization? The microstructure of highly anisotropic particles with an SRR-like geometry” – Pawlak, D.A., Turczynski, S., Gajc, M., et al., Advanced Functional Materials 20, 1116, (2010)

[7] PrAlO3-PrAl11O18 eutectic: Its microstructure and spectroscopic properties” - Pawlak, D.A., Kolodziejak, K.,Turczynski, S., Kisielewski, J., Rozniatowski, K., Diduszko, R., Kaczkan, M., Malinowski, M., Chemistry of Materials 18, 2006, pp. 2450-2457 .


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Presentation: Poster at 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17, Topical Session 9, by Krzysztof P. Orliński
See On-line Journal of 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17

Submitted: 2013-06-05 15:54
Revised:   2013-07-24 21:28