Cloaking Technology

Some of the most up to date scientific and technical information on Invisibility and cloaking technologies. It is important that we monitor and document the historical development of these technologies.

These sources are courtesy of Professor Graeme Milton from his speech at Worchester Polytech:
http://www.cmap.polytechnique.fr/edp-cs/pdf/presentation_G_Milton.pdf

Tachi and collaborators - projection cloak
http://www.saferplane.com/stealth/
Aliev et.al. 2011 - Mirages using heated carbon nanothreads

Invisibility Theory:

1. A.L Pokrobvsky, A.L Efros, "Electrodynamics of photonic crystals and problem of left-handed materials" PRL, 89, 093901 (2002).
2. A. L. Pokrovsky, A. L. Efros, "Nonlocal electrodynamics of two-dimensional wire mesh photonic crystals", Phys. Rev. B 65, 045110 (2002)
3. A. L. Pokrovsky, A. L. Efros, "Electrodynamics of metallic photonic crystals and problem of left-handed materials" , Phys. Rev. Lett. 89, 093901 (2002).
4. A. L. Pokrovsky, A. L. Efros, "Sign of refractive index and group velocity in left-handed media", Solid State Comm. 124, 283 (2002).
5. A. L. Pokrovsky, A. L. Efros, "Diffraction in left-handed materials and theory of Veselago lens", cond-mat/0202078 (2002)
6. A.L. Efros and A. L. Pokrovsky, "Diffraction in Left-Handed Materials and Theory of Veselago Lens" Physica B, 2003.
7. A. L. Pokrovsky, A. L. Efros, "New type of lenses based upon left-handed materials" cond-mat/0212312 (2002)
8. A. L. Pokrovsky, A. L. Efros, "Propagation of waves in metallic photonic crystals at low frequencies and some theoretical aspects of left-handed materials, cond-mat/0207535 (2002)
9. Y. Liu and S. Blair, "Fluorescence enhancement from an array of subwavelength metallic apertures," Optics Letters, v.28,p.507, 2003.
10. V.F. Kozhevnikov, M. Diwekar, V.P. Kamaev, Jing Shi, and Z.V. Vardeny, "Physical Properties of Gallium Infiltrated into Opal Photonic Crystal" Physica B (2003).

Submitted or in Press

1. M. Airola and S. Blair "Second-harmonic generation from an aray of subwavelength metallic aperatures" ,in preparation for Optics Letters.
2. Kamaev, A. A. Zakhidov, V. F. Kozhevnikov, and Z. V. Vardeny, "Optical studies of Bismuth and Gallium infiltrated opal photonic crystals"V. P. to be submitted to Appl. Phys. Lett.
3. V.P. Kamaev, M. Diwekar, J. Shi, and Z. V. Vardeny, "Optical and Magneto-optical studies of Cobalt 2D photonic crystals" to be submitted to Appl. Phys. Lett.
4. A. L. Pokrovsky, A. L. Efros "New lens based upon left-handed materials" submitted to Applied Optics.
5. V. L. Pokrovsky, A. L. Efros "Photonic spectra of Metallic photonic crystals" to be submitted in Phys. Rev. B.

Radar Invisibility

Barium Titanate metamaterials

Barium Titanate was actually one of the first of a new class of materials called metamaterials to be discovered. Although not confirmed, it is suspected to be one of the key ingredients in Radar invisible paints which are used to paint stealth aircraft. It is also suspected to be one of the toxic materials that was burned at Area 51 illegally resulting in toxic smoke covering the town of Rachel Nevada and several law suits being filed by individuals working on the base.

Quasicrystalline metamaterials

Since ordinary left-handed metamaterials have a limit to how small we can make them, scientists have been looking for other ways. The answer to this question lies in nanophotonics, and in a new type of material called "quasicrystals".

Nanophotonics are now being recognized as a special branch of optics, in much the same way as nanoelectronics form a special branch of electronics. Some of the technological problems that had appeared at the time of the first studies on photonic crystals, are currently in the process of being solved. However, it should be stressed that future development and applications of photonic crystals are definitively dependent on the degree of accuracy which can be achieved in the fabrication of micro- and nanostructures, and thus on the overall dimensions of the corresponding devices.

One of the most striking illustrations of the fruitfulness of research on metallo-dielectric photonic crystals is probably the development of the so-called metamaterials, which are expected to provide a new approach towards negative refraction, through the simultaneous control of the effective permittivity and the effective permeability.

Since metamaterials are dependent upon the structure of the material rather than the properties of the atoms that make up it's composition, it is possible to build photonic metamaterials using packed nanospheres. Recently major breakthroughs have occurred in Nonlinear Liquid Crystal Nano-Metamaterials which use nanosphere- and nanoshell-doped liquid crystals can produce metamaterials with a tunable refractive index!