While we're on the subject of three-d printing and "teleportation"(see yesterday's blog), we might as well talk about another thing that it is enabling to take one step closer to reality: invisibility through meta-materials engineering. This one is near and dear to my heart, because way back in my very first book, The Giza Death Star, I speculated on the possibility that special kinds of crystals could be grown, perhaps through the use of nanotechnology, which would effectively trap light inside the crystal, through a special kind of negative refraction, imagining a whole series of "dark crystals" - dark rubies, dark garnets, dark sapphires, and so on - that were brighter on the inside than they were on the outside, so to speak. And in the Giza Death Star Destroyed, in spent some time with the Bablyonian Enuma Elish epic, and Marduk's "invisibility" cloak.
It should come as no surprise that materials engineers and technicians are now entertaining very similar ideas:
"These objects are put together in precise geometrical patterns to bend waves of energy in unnatural ways.
"In particular, they reveal a property called 'negative refraction', meaning they can bend a wave backwards.
"But metamaterials with this negative refraction have presented a vexing physics problem: They reduce the strength of the wave.
"'One of the biggest problems with metamaterials is that they produce energy loss,' Professor Xin said.
"'The waves decay as they pass through the artificial material. We have designed a metamaterial that retains negative refraction but does not diminish energy.'
"In fact, the synthetic material not only prevented energy loss - it caused energy gain, with the microwave intensifying in strength as it passed through the material.
"Professor Xin achieved this by embedding battery-powered tunnel diodes – which is a type of semiconductor device - and into the new material.
"'Many people did not think it was possible to achieve energy gain along with negative refraction,' Professor Xin said.
"He first showed it was possible, with one-dimensional metamaterials, in a paper published in Physical Review Letters in 2011.
"His new findings, reported in Nature Communications, have broader implications, because they involve 3D metamaterials."