Plasmonics - cure for cancer, faster computers, and yes, invisibility
Posted On Friday, November 16, 2007 at at 3:52 PM by Eddie
Plasmonics is a new field of study that merges the classical photonics and electronics in nanoscale. Beginning the the 1980s, scientists have discovered that by squeezing light into a minuscule wire of dielectric core inside a metal, they were able to produce a resonating wave of surrounding electrons in the host metal's native sea of free electrons. They called this the surface plasmons - hence "plasmonics". Nowadays, plasmonics produced the first successful and harmless treatment for malignant cancer, and it is an innovation in the speed of computing and a breakthrough in invisibility.
Plasmons propagate like ripples on the surface of a metal, which turns out to be a much faster way of transmitting information within computer chips. The frequency of a optical signal is much higher than an electrical one - around 400,000 gigahertz verses 60 hertz. If only researchers could find a way to control the flow of electrons (they are very close) then plasmonics computing would be realized and technology would be revolutionized again.
But the real deal of now is the cure for cancer. Biochemists have engineered tiny silica particles 100 nanometers wide which are covered in a film of gold. These particles were injected into the bloodstream of the test subject, the mice with a tumor. After discovering that this material is non-toxic, they also found that these nanoshells tended to embed in the tissues of the tumor instead of other cells, since that is where more blood circulates due to its rapid growth. An infrared laser light was then shone onto the tumor, resulting in the plasmonic activity on the gold shells of the silica particles. The cancer tissues began to heat up from 37C to around 45C, where the photothermal energy killed the cancer cells while leaving the surrounding healthy cells unharmed. All signs of cancer on the mice was gone within 10 days, while the control subjects continued to be plagued by the disease. Houston Nanospectra Biosciences is currently requesting permission to conduct clinical trials of "nanoshell therapy" on cancer patients; we are very close to finally getting a real cure!
On a lighter note, plasmonics also allow the futuristic technology of invisibility. Many physicists theorize that this is highly possible. The results, as for now, yields invisibility for certain colors, or certain range of frequencies. To achieve total invisibility, all frequencies of the visible light must be covered; that will only take time. The basic idea is to make the structure's refractive index equal to air's; it would not bend or reflect light, like the classical ways of invisibility, but instead absorb the light. When it's laminated with a material that produces optical gain, the increases in intensity would offset the absorption losses, making the object invisible (in a certain selection of frequencies, for now).
The possibilities of plasmonics is quite endless. It might just replace electrical signals in the future of communication, cure cancer, and produce the world's first invisibility cloak. This is only the beginning; further exploration of the plasmonic phenomenon will return more exciting discoveries.
