January 18, 2010

Plasmonic Computers

A plasmonic laser (illustrated here) could be one component of an extremely fast plasmonic computer, giving light perhaps its tightest squeeze yet - about as small as the circuitry that moves electrons in standard electronics. Nicolle Rager Fuller

UPDATE: J Storrs Hall, President of the Foresight Institute, noted recent progress in working with graphene and a patent on surface-plasmon fluidic logic.

* Cornell has been experimenting with growing full-scale, four-inch graphene wafers, which would further demonstrate the manufacturing potential of graphene-based electronics.

* Nextbigfuture covered - A new digital "electronics" concept is introduced. The concept, called nano-electron-fluidic logic (NFL), is based on the generation, propagation and manipulation of plasmons in a two-dimensional electron gas behaving as an electron fluid.

NFL gates are projected to exhibit femtojoule power dissipations and femtosecond switching speeds at finite temperatures. NFL represents a paradigm shift in digital technology, and is poised as a strong candidate for "beyond- CMOS" digital logic.

* Operates with far less heat and more efficient energies (femtojoules)
* Faster switching speeds (femtosecond)
* higher density potential for devices
* Terahertz operating speeds for chips
* Propogation velocity of electron fluid is hundreds of times faster than electrons in current CMOS
* Device construction is compatible with current lithography

Science news had Better living through plasmonics

Nextbigfuture has covered plasmon nanolasers before and how they could enable onchip photonic communication.

Nextbigfuture covered the work at UC berkeley to shatter the limits on lasers using plasmonic lasers

There is European work to make better optical ring resonators and other components of an all optical plasmonic computer before 2020 Optical ring resonators are candidates for tiny waveguides in optical plasmonic computers

Wikipedia describes plasmons

Plasmons can be described in the classical picture as an oscillation of free electron density against the fixed positive ions in a metal. To visualize a plasma oscillation, imagine a cube of metal is placed in an external electric field to the right. Electrons will move to the left side (uncovering positive ions on the right side) until they cancel the field inside the metal. Now we switch the electric field off, and the electrons move to the right, repelled by each other and attracted to the positive ions left bare on the right side. They oscillate back and forth at the plasma frequency until the energy is lost in some kind of resistance or damping. Plasmons are a quantization of this kind of oscillation. Plasmons play a large role in the optical properties of metals.

Plasmons have been considered as a means of transmitting information on computer chips, since plasmons can support much higher frequencies (into the 100 THz range, while conventional wires become very lossy in the tens of GHz). For plasmon-based electronics to be useful, an analog to the transistor, called a plasmonster, must be invented.

To adapt a computer’s binary system of 1s and 0s for light, scientists also have to figure out the best ways to, in essence, flicker light on and off while it is carried along in a plasmon wave.

A group at Caltech recently invented a device — dubbed a plasMOStor, or a plasmonic modulator — that could help in this quest. The research team, led by physicist Harry Atwater, published its results in Nano Letters in January. PlasMOStors give scientists a way to modulate light by applying voltage that puts light waves and plasmonic waves either in or out of sync with each other — which allows the signal to be turned on and off.

Even getting a plasmon wave started can be hard in some cases. “You can’t just send light into a metal and expect it to couple [with electrons],” says Jennifer Dionne of UC Berkeley. “It’s difficult to do unless someone gives you a really big push.”

Nanoletters journal - PlasMOStor: A Metal−Oxide−Si Field Effect Plasmonic Modulator

Realization of chip-based all-optical and optoelectronic computational networks will require ultracompact Si-compatible modulators, ideally comprising dimensions, materials, and functionality similar to electronic complementary metal−oxide−semiconductor (CMOS) components. Here we demonstrate such a modulator, based on field-effect modulation of plasmon waveguide modes in a MOS geometry. Near-infrared transmission between an optical source and drain is controlled by a gate voltage that drives the MOS into accumulation. Using the gate oxide as an optical channel, electro-optic modulation is achieved in device volumes of half of a cubic wavelength with femtojoule switching energies and the potential for gigahertz modulation frequencies.

The 7 page pdf of the PlasMOStor: A Metal−Oxide−Si Field Effect Plasmonic Modulator

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