Chemists at the University of California have grown the world’s smallest laser, which is one thousand times thinner than a human hair, and gold played an integral role in the process.
The infinitesimal device can be used more widely than gallium arsenide lasers, commonly used in laser pointers. Gallium arsenide lasers are several micrometres wide, or about 100,000th of an inch, whereas the new “nanolaser” is about 100th the size.
A research team led by Prof. Peidong Yang created the nonolaser, which consists of pure crystals of zinc oxide, by a hot vapour procedure known as “epitaxy.” The procedure involves painting a gold catalyst on a piece of sapphire and then heating the gold. This causes the metal to form regularly spaced nanocrystals, which, in turn, stimulate the growth of pure zinc oxide wires 20-150 nanometres in diameter.
“This technique is compatible with current industry methods,” Yang says.
Under an electron microscope, the nanolasers look like bristles of a brush; bunched together, they are bright enough to be used in applications.
For example, so-called “lab-on-a-chip” devices contain small laser analysis kits capable of identifying minuscule amounts of chemicals or other substances for environmental or medical testing. The lasers could also be used in optical computing applications, such as memory storage.
— The preceding is an excerpt from Gold News, published by the Washington, D.C.-based Gold Institute.
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