A group of researchers in the United States is currently trying to develop new methods of using lasers for advanced applications, such as in the field of spintronics and for improving quantum computing. The group is convinced that it is on the right track, as its latest results indicate.
At this point, people have come to take for granted the continued evolution of modern electronics. New microprocessors and transistors are being created annually, and each of them is better and smaller than the ones that came before. However, Moore's Law does not allow for this process to go on indefinitely.
Currently, the materials used to make complex computer chips are starting to reach their physical limits, meaning that a new approach to the entire field is needed. Spintronics is one option. Unlike electronics, it encodes data in the spin of their electrons.
Lasers are an especially effective means of controlling this spin, say investigators at the City College of New York (CCNY) and the University of California in Berkeley
(UCB). They are currently using lasers to control the fundamental nuclear spin properties of semiconductor materials.
Details of the work, which was led by CCNY investigators Carlos Meriles and Yunpu Li, and UCB colleagues Jeff Reimer and Jonathan King, appear in a recent issue of the top scientific journal Nature Communications.
“But we have even bigger fish to fry. We can use these same laser techniques to manipulate spin states for a radically new type of computing. For now, ‘quantum computing’ relies on expensive, exotic materials or on temperatures very close to absolute zero,” Reimer explains.
“Our laser techniques can allow quantum computing to become far more practical and inexpensive. With lasers, this research can be conducted with standard semiconductor materials,” the expert adds.
Currently, transistors are being built at a scale of 28 nanometers. The space between them is smaller than the space between air molecules in the atmosphere. In order to get a sense of scale, consider that a human hair is around 100,000 nanometers wide.
At such small scales, electrons start to become incapable of performing their functions, due primarily to interferences and effects from quantum mechanics. Reimer says that this is where spin comes into play.
“Spin is the characteristic of the neutrons, protons and electrons that make up all matter. It is spin that allows us to get images inside the human body using magnetic resonance imaging (MRI),” he says.
According to the expert, lasers are an excellent means of controlling the spin states of electrons. Without them, extremely powerful magnets would have to be used, and this would be impractical for consumer applications.