Optical Transistors for Quantum Computing

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The core of the optical transistor is made out of two mirrors. Between them lies a sealed cavity containing a gas of supercooled cesium atoms. The mirrors are set at a distance which is precisely calibrated to the wavelength of light, so that they act as an optical resonator, able to bounce light back and forth between them while preserving its phase.

Light can be described as either a particle or an electromagnetic wave. In its particle description, photons simply ought to bounce off the first mirror and return to the source; however, in accordance with the wave description, light actually goes through the first mirror and enters the resonator, bouncing back and forth and eventually creating a large electromagnetic field that cancels out the effects of the two mirrors, allowing photons to pass through.

But when a single "gate photon" is fired into the resonator and hits the cesium atoms at a different angle than all the others, this changes the physics of the cavity to such an extent that only about 20 percent of the light can now get through the resonator.

In practice, the device acts as a light switch which is itself controlled by a light signal (the "gate photon") in much the same way that, in a standard transistor, a "gate voltage" can control the current flowing between the two ends of the device.

Building an optical quantum computer
As already discussed, optical computing could bring us much faster and more power-conscious CPUs in the years to come; however, important as they may be, the more interesting applications aren't with traditional computer architectures, but rather in the field of quantum computing.

Quantum computing, still in its infancy, harnesses the quirks of quantum mechanics to create more powerful computers. One of such peculiarities is superposition, the counterintuitive ability of a quantum bit ("qubit" for short) to be assume more than one value – "0" and "1" – at the same time.

Maintaining superposition is crucial, but it is very challenging because most atoms tend to interact with each other and destroy their superposition state (early quantum computer designs used ions trapped in electric fields, with mixed results at best). But photons don't easily interact with each other, meaning that superposition would be much easier to store safely in an optical quantum computer.

Quantum computing – what's it for?
Being able to switch an optical gate with a single photon opens the possibility of creating arrays of optical circuits, all of which are in a superposition state. "If the gate photon is there, the light gets reflected; if the gate photon is not there, the light gets transmitted," Vladan Vuletić at MIT, who led the work, explains. "So if you were to put in a superposition state of the photon being there and not being there, then you would end up with a macroscopic superposition state of the light being transmitted and reflected."
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http://www.gizmag.com/optical-transistor-quantum-computing/28203/

The gate photon would be there, destroying the superposition state. In a superposition state everything is at once, then interaction destroys it.
 
OTs have far-reaching applications. I'm hoping to go to MIT next fall to help build a Quantum computer.
 
The team from MIT's Research Laboratory of Electronics, in partnership with Harvard University and the Vienna University of Technology, have released details of their experimental realisation of an optical switch which can be controlled using a single photon. As a result, it's possible for light to interact with light - something that isn't normally possible, with two photons meeting each other in a vacuum simply ignoring each other and passing straight on through.
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http://www.bit-tech.net/news/hardware/2013/07/05/optical-transistor/1
 
I analyzed an optical computer back in 1982. An UFO crashed in Springfield, MA where my technician lived. He brought in some of the wreckage and we analyzed it with our 1000 power optical microscope and our x-ray fluorescence unit. We determined that it was an optical computer core. It was manufactured from micron sized crystals like ruby, emerald, silica, saphire, etc., etc., etc. The crystals were all aligned in a highly ordered fashion. Not like a mineral rock found on the Earth that has large and small crystals aligned at random and only of one or two types of crystals. I follow optical computer research to this date and I am amazed that the researchers have not figured this out. They use LED lasers, photonic crystals, etc. and never get them working. The whole manufacturing plant that made glass contact refractories figured this out and talked about it openly. We were all terminated with no reason. The cover up! This country is weird! Find advanced technology that could help the world and they bury it. Do you think this is a science fiction tale???
 
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