That is exactly what Seagate has done. Three years ago they demonstrated 250 gigabits per square inch density using the technology. Since then, Gage says, they’ve made substantial improvements in two areas: the recording head and the iron-platinum medium.
The biggest issue with the new head is that it needs to focus light onto 25-nanometer-wide spots, which is tough with conventional lens-based optics. So Seagate uses a parabolic mirror that focuses light down to a quarter of its wavelength, making 100-nanometer spots. To tighten that even more, Seagate researchers use a tiny gold antenna that collects light and reemits it at a 30-nanometer spot. “It’s a gold piece that has to be appropriately shaped,” Gage says. “We’ve tried a number of different antenna shapes.”
The iron-platinum medium poses its own difficulties. “You need a smooth platter, a very good granular microstructure,” Gage says. “You have to be able to grow the right crystalline structure.” Plus, he says, heat spreads in the magnetic material. “You have to build layers in there to control the way the heat flows laterally and vertically.”
Seagate’s demo shows that they have overcome these significant engineering challenges, Kryder says. “This is exciting news.”
Right now, Seagate uses an external laser to shine light on the parabolic mirror. But Gage says they have already put a laser inside a recording head.
Nonetheless, Gage says, much more work is needed before Seagate has a commercial product: “Putting together the head, magnetic media, [electronic control circuits], and firmware and getting them into a hard drive is significant work.”