Future Technology Trends

Surface plasmons are oscillations of charge density located on metal surfaces. They are of interest due to their ability to enhance the performance of nanophotonic devices.  Plasmonic circuits may eventually have much higher frequencies than what is possible with current electronics.  Some scientists have claimed that CPU’s based on this technology might operate at speeds over 100 times greater than what can be bought at a store today.  With grandiose proclamations like this, there is reason to be skeptical.  For high performance computing, the limitations of current CMOS chips are obvious.  While it is too soon to say whether this will actually find its way into the market, there have been promising new developments.  Chinese scientists have been able to synthesize logic gates based on the technology.  Logic gates are the fundamental units that allow microchips to swiftly carry out calculations.  

Cascaded logic gates in nanophotonic plasmon networks

Optical computing has been sought out after for decades as a novel strategy for moving beyond the fundamental performance limits of current semiconductor-based electronic devices, but viable on-chip integrated logic units and cascade devices have not yet been reported in the literature.

Here we show that a plasmonic binary NOR gate, a ‘universal logic gate’, can be attained by using cascaded OR and NOT gates in four-terminal plasmonic nanowire network. This discovery provides a path for the development of nanophotonic on-chip processor architectures for future optical computing technologies.

A 44 nm plasmonic  ”spaser” had been created a few years ago.  More work is being done all the time to perfect these miniaturized lasers.

Spaser as Nanoscale Quantum Generator (PDF)

This prospective spaser will further broaden both applied and fundamental horizons of nanoscience, in particular, allowing fast processors working between a value of 10 to 100 Terahertz clock speed. Other prospective applications are in  ultradense and ultrafast information storage, ultrasensing and biomedicine. The spasers are based on metals and are extremely resistive to the effects of ionizing radiation,  microwave radiation, high temperatures, and other adverse environments.

Photons can carry more information due to a high frequency and their movement generates less heat than an electrical current.  However, the diffraction limit has made it hard to shrink conventional photonic devices much further.  Plasmonics allows researchers to confine light frequencies to much smaller areas than their wavelength would suggest possible.

Some sort of silicon integrated photonics might be ideal as it could piggy back on all of the developments with existing circuits.

Plasmonics: Electrifying plasmonics on silicon

The realization of electrical sources of surface plasmon polaritons utilizing complementary metal oxide semiconductor technology is a significant step towards silicon-compatible nano-scale photonic devices.

If they cannot be used for faster microprocessors, there are a variety of other applications that seem more probable.  This is especially true if the expense is too high.  They may only end up being found in specialized niche products.