Silk
'Invisibility Cloak' Created By Scientists
At the moment the cloak only works for light
outside the visible spectrum, in the terahertz
band between radio and infrared. But its
developers, at Boston University and Tufts
University, believe that it could be made to
work at far smaller wavelengths, possibly even
including visible light, according to
Discovery News. The researchers hope it will
have applications in medical science, as well
as opening the possibility of making people or
objects invisible. The "metamaterial"
is made of silk covered in tiny gold
structures, each a tiny spiral known as a
"split ring resonator" or SSR. SSRs
have fascinating effects on light - they can
absorb, or reflect, all the light at a given
wavelength, or bend that light around an
object. The silk metamaterial has 10,000 SSRs
per square centimetre. Normally, terahertz
waves would pass through silk unaffected. But
the new meta-silk resonated when the light
struck it. Since silk is
"biocompatible" - it doesn't spark
an immune reaction when implanted in the human
body - the meta-silk can be used widely in
medicine. Fiorenzo Omenetto, one of the Tufts
researchers, told Discovery: "This is an
unusual angle for a metamaterial because of
silk's ability to interface with the human
body."