Defense Intelligence Reference Document Aerospace Applications of Programmable Matter

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"Impossible" Materials
When natural materials are shaped and combined in macroscopic ways, it becomes
possible to produce what Roger Bacon described as "natural magic": devices such as
mirrors, lenses, polarizers, magnets, wires, semiconductors, fluorescent dyes, and
phosphorescent screens that glow in the dark. We take these devices for granted, but
to our primitive ancestors they would have seemed supernatural, as indeed they are in
the sense of not occurring naturally.
However, by combining the same materials in nanostructured ways, we achieve a
higher order of magic: Bragg mirrors that reflect a single wavelength while transmitting
all others, superlenses that defy Newton's diffraction limit to focus with unnatural
sharpness, superstrong magnets that measure the world around them with
unprecedented sensitivity, photoluminescent materials that absorb light in a broad
range of wavelengths and re-emit it in a single brilliant color. Soon we may have high-
temperature superconductors and even materials that are functionally invisible.
One such "impossible" material hypothesized is the nanostructured "metapolarizer."
Where classical polarizers either reflect or absorb half the light that hits them (typically
resulting in energy wastage of SO percent or higher), a metapolarizer simply ignores
one polarity of light and converts or rotates or "retards" the other. This principle can be
harnessed, for example, to double the battery life of a laptop display or to double the
brightness of a flat-screen TV.
However, even these magical materials are "static"; that is, their properties are fixed at
the time of manufacture. The greatest revolution in materials science may in fact come
from materials capable of changing their properties on demand.
Advantages of Dynamic Materials
Leaving behind the world of static materials, we come to a sort of programmable magic
whose fruits already include switchable mirrors, dynamic optical filters, deformable
lenses, magnets and polarizers that appear and disappear on command. Less
glamorous but equally important are such "behind the scenes" capabilities as tunable
electrical conductivity, tunable bandgap semiconductors, tunable lasers, and tunable
photonic crystals.
However, the ultimate exemplar of designer materials will be multifunctional smart
materials, which are capable not only of switching a particular property on and off but
of changing their properties-indeed, their very purpose-on demand.
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