Now that was a relevant and interesting article. Thanks.
But it points out the considerable obstacles that still lie ahead, and provides a history of why optical computing has failed to materialize:
Crucially, though, the development of spasers has sparked the hope that one of the great scientific disappointments of the past decades - the unfulfilled promise of optical computing - may yet be turned into triumph.
On the face of it, optical computers, which use light rather than currents of electrons to process information, are a great idea. Electrons are easy to manipulate and process, but they tend to get bogged down as they pass through metals and semiconductors, colliding with atoms and bouncing off them in ways that limit the speed and fidelity of information transmission. Photons, by contrast, can withstand interference, and are above all fast, in theory zipping around a chip at close to the cosmic speed limit.
In the 1990s, various groups claimed to be getting close to making the dream of optical computing a reality. That included a concerted effort at the world-famous Bell Laboratories in Murray Hill, New Jersey, where the building block of microelectronic circuits, the transistor, was invented in 1947. Researchers there and elsewhere hit a snag, however. The very fleet-footedness that made photons perfect for high-speed communications made them almost impossible to pin down and use for sensible processing of data.
"Optical computing has a chequered history, particularly the boondoggle at Bell Labs," says Harry Atwater, a physicist at the California Institute of Technology in Pasadena. All the efforts foundered when it came to producing anything like a transistor: a tiny, low-power device that could be used to toggle light signals on and off reliably.
In theory, a controllable laser would do this trick, if not for one problem - lasers devour power. Even worse, they are huge, relatively speaking: they work by bouncing photons around a mirrored cavity, so the very smallest they can be is about half the wavelength of the light they produce. For green light, with a wavelength of 530 nanometres, that means little change from 300 nanometres. Electrical transistors, meanwhile, are approaching one-tenth that size.
You see where this is leading. Spasers are a tiny source of light that can be switched on and off at will. At a few tens of nanometres in size, they are just slightly bigger than the smallest electrical transistors. The spaser is to nanoplasmonics what the transistor is to microelectronics, says Stockman: it is the building block that should make optical information-processing possible.
Inevitably, there will be many hurdles to overcome. For a start, Noginov's prototype spaser is switched on and off using another laser, rather than being switched electrically. That is cumbersome and means it cannot capitalise on the technology's low-power potential. It is also unclear, when it comes to connecting many spasers together to make a logic gate, how input and output signals can be cleanly separated with the resonant spherical spasers that have so far been constructed.
Additionally, the spasers they are talking about will NOT be using the LWLG materials, they seems to be reliant on other materials, specifically: "a circular particle just 44 nanometres across. It consists of a gold core contained within a shell of silica, speckled with dye molecules"
The only thing we can hope for is that this sparks interest in optical computing in general.
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