A diamond aerogel has been hammered out of a microscopic anvil. Image: Kwei-Yu Chu/LLNL
combining high pressure with high temperature, Livermore researchers have created a
nanocyrstalline diamond aerogel that could improve the optics for something as
big as a telescope or as small as the lenses in eyeglasses.
are a class of materials that exhibit the lowest density, thermal conductivity,
refractive index, and sound velocity of any bulk solid. Aerogels are among the
most versatile materials available for technical applications due to their many
exceptional properties. This material has chemists, physicists, astronomers,
and materials scientists utilizing its properties in myriad applications, from
a water purifier for desalinizing seawater to installation on a NASA satellite
as a meteorite particle collector.
new research appearing in Proceedings of the National Academy of Sciences,
team created a diamond aerogel from a standard carbon-based aerogel precursor
using a laser-heated diamond anvil cell.
diamond anvil cell consists of two opposing diamonds with the sample compressed
between them. It can compress a small piece of material to extreme pressures,
which can exceed 3 million atmospheres. The device has been used to recreate
the pressure existing deep inside planets, creating materials and phases not
observed under normal conditions. Since diamonds are transparent, intense laser
light also can be focused onto the sample to simultaneously heat it to
thousands of degrees.
new form of diamond has a very low density similar to that of the precursor of
around 40 mg per cubic centimeter, which is only about 40 times denser than air.
diamond aerogel could have applications in antireflection coatings, a type of
optical coating applied to the surface of lenses and other optical devices to
reduce reflection. Less light is lost, improving the efficiency of the system.
It can be applied to telescopes, binoculars, eyeglasses, or any other device
that may require reflection reduction. It also has potential applications in
enhanced or modified biocompatibility, chemical doping, thermal conduction, and
electrical field emission.
creating diamond aergoels, lead researcher Peter Pauzauskie, a former Lawrence fellow now at the Univ. of Washington,
infused the pores of a standard, carbon-based aerogel with neon, preventing the
entire aerogel from collapsing on itself.
that point, the team subjected the aerogel sample to tremendous pressures and
temperatures (above 200,000 atmospheres and in excess of 2,240 degrees
Fahrenheit), forcing the carbon atoms within to shift their arrangement and
create crystalline diamonds.
success of this work also leads the team to speculate that additional novel
forms of diamond may be obtained by exposing appropriate precursors to the
right combination of high pressure and temperature.