Fiber optic cables can transmit over a terabyte of information per second – but that doesn't mean there still isn't room for improvement. One of those improvements, which was officially announced today, involves replacing the silica glass core of fiber optic strands with semiconductive zinc selenide. This new class of fiber optics, invented and created at Penn State University, is said to "allow for a more effective and liberal manipulation of light." The technology could have applications in the fields of medicine, defense, and environmental monitoring.
According to Penn State project leader Prof. John Badding, the arrangement of atoms in glass is haphazard, which impedes the passage of light through them. Crystalline substances like zinc selenide, however, have a highly-ordered atomic structure, which allows light to be transported over longer wavelengths.
To make the fibers, the scientists stared with hollow glass capillaries. Using a unique high-pressure chemical-deposition technique, they were then able to deposit the zinc selenide waveguiding cores inside of them.
It was observed that the new fibers were better than conventional ones at changing the color of light. "When traditional optical fibers are used for signs, displays, and art, it's not always possible to get the colors you want," said Badding. "Zinc selenide, using a process called nonlinear frequency conversion, is more capable of changing colors."
The zinc selenide fibers were additionally found to be superior at transmitting not only visible light, but also longer-wavelength infrared light – something that poses a challenge for conventional glass fibers. "Exploiting these wavelengths is exciting because it represents a step toward making fibers that can serve as infrared lasers," Badding stated. "For example, the military currently uses laser-radar technology that can handle the near-infrared, or 2 to 2.5-micron range. A device capable of handling the mid-infrared, or over 5-micron range would be more accurate. The fibers we created can transmit wavelengths of up to 15 microns."
Such laser-radar technology could be used not only by the military, he added, but also for detecting molecules of toxic substances in the atmosphere, or for laser-assisted surgical techniques.
The research was published today in the journal Advanced Materials.
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