Although the 10-nanometer gap is minuscule, researchers could build a new type of optical reading and writing head using the technology, suggests Crozier. The magnetic storage industry, he points out, works with a similarly small gap between the head and medium.
Using nano antennas to focus optical light is not an entirely new idea, Crozier says, but their work, published in Applied Physics Letters, is the first time an antenna has been integrated directly onto a laser. This offers an advantage in production because the light source and antenna are in one package. “It’s extremely compact and easier to use because alignment with the laser and the antenna is all done in fabrication,” he says.
There’s a lot of research activity to reduce the spot size of light, but it’s especially attractive to the data storage industry, says Bae-Ian Wu, a research scientist in the Research Laboratory of Electronics at MIT. Using a nano antenna is just one way to gain “super resolution smaller than the wavelength of light.” But, he says, the Harvard researchers work “is very good in the sense that they are doing optical experiments to back up their theory, while some papers are only in the realm of theory.” The Harvard scientists, he adds, “just did it.”
Crozier says his team is exploring fabrication techniques that can further decrease the spot size to 20 nanometers. They’re also exploring alternatives to the gold metal that currently coats their nano rods. Silver, for instance, could focus light more efficiently than gold at the wavelengths used by the consumer electronics industry.