Wi-fi on an atomic scale - the perfect fit

ScienceDaily (Feb. 28, 2012) — We know since the dawn of modern physics that although events in our everyday life can be described by classical physics, the interaction of light and matter is down deep governed by the laws of quantum mechanics. Despite this century-old wisdom, accessing truly quantum mechanical situations remains nontrivial, fascinating and noteworthy even in the laboratory. Recently, interest in this area has been boosted beyond academic curiosity because of the potential for more efficient and novel forms of information processing.

Alister's SoftMachine outfit is a morphing, colour changing outfit that receives instructions from both Alister and the world's most powerful supercomputer. The wireless function is built into the nanomaterial of the outfit.
Here's a rehash exercise I undertook of the Science Daily article  just to help me understand what had been achieved


 "A single atom or molecule acts as a quantum bit processing signals delivered via single photons. 
It is possible to set up a situation where single molecules can be detected and single photons generated. 
The problem is putting together a simple one on one interaction because billions of photons per second are usually impinged on a molecule to obtain a signal from it.
First off, you  would have to find a suitable source of single photons, which have the proper frequency and bandwidth. Although lasers come in different colours and specifications, something that fires single photons can't be bought at Maplins or Radio Shack
One common way to get around this difficulty in atomic physics is to build a cavity around the atom so that a photon remains trapped for long enough times to increase the chances of a 1-1 interaction. 
 And it's been done. Connecting a single flying photon with a single molecule. 
So a team of scientists (at ETH Zurich and Max Planck Institute for the Science of Light in Erlangen) led by Professor Vahid Sandoghdar made something that spits out single photons. 
How? Well they cheated a little by using a photon release event that happens naturally. When an atom or molecule absorbs a photon it makes a transition to a so-called excited state. After a few nanoseconds (one thousand millionth of a second) this state decays to its initial ground state and emits exactly one photon. 
So the group used two samples of fluorescent molecules embedded in organic crystals and cooled them to about 1.5 K (-272 °C). Single molecules in each sample were detected by a combination of spectral and spatial selection.
To generate single photons, a single molecule was excited in the “source” sample and when the excited state of the molecule decayed, the emitted photons were collected and tightly focused onto the “target” sample at a distance of a few meters. 
The team had to (1) make sure the photon and the molecule had the same frequency; and (2)  get the single photons to interact with the target molecule in an efficient manner. 
Not that easy when the focus of a light beam cannot be smaller than a few hundred nanometers; while a molecule is about one nanometer in size (100,000 times smaller than the diameter of a human hair); which would lead to most of the incoming light (photons) going around the molecule, i.e. without them seeing each other. 
Here's the 'but';  if the incoming photons are resonant with the quantum mechanical transition of the molecule, the molecule acts more like a prefect little catchers glove to the area of the focused light and grabs the light waves in its vicinity. 
The experimental work was performed at ETH Zurich before the group of Prof. Sandoghdar moved to the newly founded Max Planck Institute for the Science of Light in Erlangen in 2011."