Historical research guide · 0370 · 2010

Metamaterials for Aerospace Applications

DIA / AAWSAP contractor

In one minute

Metamaterials are built rather than found: arrange metal rings and wires much smaller than a wavelength and the resulting medium has an electrical response no natural substance offers, including a negative refractive index, where the energy and the wave crests travel in opposite directions. This survey, written for the Defense Intelligence Agency by a working laboratory, walks through what that buys an aircraft or a spacecraft. Lenses that beat the diffraction limit and read out an image in the far field, with no scanning probe. Waveguides that slow a light pulse or stop it altogether, so a component whose length is set by the speed of light can be shrunk. Absorbers tuned so precisely that a satellite could recharge overnight on the Earth’s own infrared glow, or an airborne platform could be powered by a laser from the ground through a clear window in the atmosphere. The author reports his own bench results and names the next two measurements.

Connection

The thesis holds that the bottleneck to using the vacuum is materials science rather than theory, and this is the DIRD that treats materials as the whole problem: engineer the medium and you engineer how light moves through it. That is the same move as metric engineering in chapter 4, one level down, and chapter 1 counts it as evidence of what the programme was actually reading.

From the source

A metamaterial is an artificial medium whose properties cannot be found in naturally occurring materials; a negative refractive index requires both the electric permittivity and the magnetic permeability to be negative, and in that case the Poynting vector, which sets the direction of energy flow, and the phase velocity point in opposite directions.Definition of Metamaterials, p. 1
It is the sub-wavelength size of the unit cell that distinguishes metamaterials from photonic crystals: split ring resonators are designed with large capacitance so their resonance is low, and the example cell operating at 10 GHz is one tenth of a wavelength across — this miniaturisation is what makes metamaterials interesting for aerospace, where weight and size are essential.Definition of Metamaterials, pp. 1–4; Figure 1
Sub-diffraction imaging no longer needs a near-field scanning microscope: a silicon-carbide super-lens imaged one-twentieth-wavelength holes buried under a silicon dioxide layer, and a hyper-lens of sixteen alternating silver and alumina layers operating at 400 nanometres resolved a line pair 35 nanometres wide at 150 nanometre spacing and magnified it to 350 nanometres, where an ordinary microscope can see it.Applications to Sub-Diffraction Imaging, pp. 6–10; Figures 6 and 7
The author’s laboratory has fabricated silica-silicon-carbide-silica indefinite-permittivity material and measured the counterintuitive prediction directly: in the band where the parallel permittivity turns negative, the first sub-diffraction diffractive order propagates through the medium with less attenuation than the zeroth radiation-zone order — the first of the two milestones that must precede true far-field super-lens imaging.pp. 11–15; Figures 11 and 13
Light can be brought to a standstill in a tapered waveguide with a negative-index core, each frequency component halting at a different core thickness to form a trapped rainbow; separately, a plasmonic molecule pairing a radiative antenna with a subradiant dark antenna reproduces electromagnetically induced transparency and slows light by a factor of thirty or more.Applications to Circuits and Waveguide Miniaturization, pp. 16–19; Figures 15, 16 and 17
A perfect absorber is made by matching the permittivity to the permeability at resonance so reflection goes to zero: a 6-micron terahertz film one fiftieth of a wavelength thick reached 70 percent absorptivity, an absorption coefficient of 2,000 per centimetre, and an impedance-matched negative-index absorber at 1,550 nanometres holds absorption near 0.97 out to 30 degrees of incidence — enough for a satellite to scavenge the Earth glow at night, or for an airborne platform to be powered by a ground-based infrared laser through the atmospheric window.Metamaterials for Energy Harvesting, pp. 20–23; Figures 18, 19, 20 and 21

The way in

https://documents2.theblackvault.com/documents/dia/AAWSAP-DIRDs/DIRD_22_Metamaterials_for_Aerospace_Applications.pdf

Historical source-access record. This guide links to the original; it does not reproduce the paper text.

Defense Intelligence Reference Document, Acquisition Threat Support. DIA-08-1004-006, 6 April 2010 (ICOD: 1 December 2009), produced under the Defense Intelligence Agency Advanced Aerospace Weapon System Applications (AAWSA) Program. Released under FOIA and published by The Black Vault. AUTHOR. Withheld under FOIA exemption (b)(6), and the preparing office under 10 USC 424. Internal evidence points to the metamaterials group at the University of Texas at Austin — the paper says ‘the author’s research group at UT-Austin has designed the first Plasmonic Negative Index Metamaterials super-lens’, reports its own in-house fabrication of silica-silicon-carbide indefinite-permittivity multilayers, and cites that group’s published review of optical plasmonic negative-index metamaterials — but the released copy names no one, so this is an inference and not an attribution. INCOMPLETE RELEASE. The released PDF is 28 pages and its text ends mid-sentence on printed page 23; printed pages 24 to 31 are absent, which removes the end of the energy-harvesting section and the whole of Nonlinear Non-Reciprocal Chiral Metamaterials (p. 27), Tunable Switchable Metamaterials (p. 30), Summary and Conclusions (p. 31) and References (p. 31). Those sections are listed in the report’s own contents page and are summarised here from that contents page and from the four-bullet overview on pages 5 and 6, which the release does contain. TEXT. Full text below, pages 1 to 23 as released. The document carries a copyright warning against further dissemination of its photographs, so the twenty-six figures are not reproduced; their captions are kept because several carry the physics. Four display equations are too damaged in the scan to reproduce and are marked where they occur; the quantities they define are stated in the surrounding prose. Greek letters, exponents, micro symbols and chemical subscripts mangled by the scan are restored, and inequalities are written out in words so the page renders. A few figure cross-references in the released copy are off by one; they are reproduced as printed.

How to cite it

DIA / AAWSAP contractor (2010) Metamaterials for Aerospace Applications https://documents2.theblackvault.com/documents/dia/AAWSAP-DIRDs/DIRD_22_Metamaterials_for_Aerospace_Applications.pdf

Where it sits in the curriculum

The reference documents and the institutional record