Product Sector: Energy → Energy Usage → Light Emission
The production of light emission technologies in a standard CMOS process offers the promise to transform the semiconductor integrated circuit market for decades to come. Applied Plasmonics technology will support both current and future generations of microprocessors and will reduce the growing gap between the ever-increasing computing power of leading-edge microprocessors and the inability to quickly move data on and off chip.
Applied Plasmonics, a fabless semiconductor company, has invented a practical, mass-market use for devices based on surface plasmons. The new technology employs nano-antennas manufactured in a single layer to generate visible light.
Applied Plasmonics' technology is a departure from other nano-technologies. Standard large volume production CMOS lithography is used to manufacture active CMOS circuits and nano-structures on a single silicon substrate.. Applied Plasmonics? technology generates light using nano-antennas that radiate photons.
Unlike LEDs (light emitting diodes) primarily used for displays and/or illumination, PEDs (Plasmon Enabled Devices) are easier to manufacture and are more efficient.
Ok, so what is a plasmon? Plasmons are a physics phenomenon based on the optical properties of metals; they are represented by the energy associated with charge density waves propagating in matter through the motions of large numbers of electrons. Electrons, in a metal, screen an electric field. Light of a frequency below the plasma frequency is reflected. Electrons cannot respond fast enough to screen above the plasma frequency, and so such light is transmitted. Most metals tend to be shiny in the visible range, because their plasma frequency is in the ultraviolet. Metals such as copper have their distinctive color because their plasma frequency is in the visible range. The plasma frequency of doped semiconductors is generally in the infrared range.
Those plasmons that are confined to surfaces and which interact strongly with light are known as surface plasmons. The interface between a conductor and an insulator is where surface plasmons propagate; bound to the surface between the two, they exponentially decay into both media.
Plasmons have a variety of potential uses. Plasmon wires can be much thinner than conventional wires, and could support much higher frequencies, so plasmons have been considered as a means of transmitting information on computer chips. The extremely small wavelengths of plasmons mean that they could be utilized in high resolution lithography and microscopy. Surface-plasmon-based sensors find uses in gas sensing, biological environments such as immuno-sensing and electrochemical studies; they are currently commercially available in some of these applications.
Metallic nano-particles exhibit strong colors due to plasmon resonance, which is the phenomenon that gives stained glass its color. The strong pure colors of medieval stained glass windows are sometimes ascribed to the impurities of the glass. However, metals or metallic oxides are what actually give glass color: gold gives a deep ruby red; copper gives blue or green, iron gives green or brown, and so forth. Plasmons on the surface of the gold nano-particles (i.e. at the interface with the glass) move such that they absorb blue and yellow light but reflect the longer wavelength red to give the glass a characteristic ruby color; the same is true of the other metals/ metal oxides, insofar that they selectively absorb some wavelengths, but reflect others.