Twisted Light From a Vortex Laser

Vortex laser: Orbital angular momentum microlaser to twist lasing radiation directly at microscale (Source: Univ. at Buffalo SUNY)

Vortex laser: Orbital angular momentum microlaser to twist lasing radiation directly at microscale (Source: Univ. at Buffalo SUNY)

Like a whirlpool, a new light-based communi­cation tool carries data in a swift, circular motion. The optics advance­ment could become a central component of next generation computers designed to handle society’s growing demand for information sharing. It may also be a salve to those fretting over the predicted end of Moore’s Law, the idea that researchers will find new ways to continue making computers smaller, faster and cheaper. “To transfer more data while using less energy, we need to rethink what’s inside these machines,” says Liang Feng, assistant professor in the Depart­ment of Electrical Engi­neering at the University at Buffalo’s School of Engi­neering and Applied Sciences.

For decades, researchers have been able to cram evermore compo­nents onto silicon-based computer chips. Their success explains why today’s smartphones have more computing power than the world’s most powerful computers of the 1980s, which cost millions in today’s dollars and were the size of a large file cabinet. But researchers are running into a bottleneck in which existing techno­logy may no longer meet society’s demand for data. Predic­tions vary, but many suggest this could happen within the next five years.

Researchers are addressing the matter in numerous ways including optical communi­cations, which uses light to carry information. Examples of optical communi­cations vary from old lighthouses to modern fiber optic cables used to watch television and browse the internet. Lasers are a central part of today’s optical communi­cation systems. Researchers have been manipulating lasers in various ways, most commonly by funneling different signals into one path, to carry more infor­mation. But these techniques — speci­fically, wavelength-division multiplexing and time-division multi­plexing — are also reaching their limits.

The UB-led research team is pushing laser technology forward using another light mani­pulation technique called orbital angular momentum, which distri­butes the laser in a cork­screw pattern with a vortex at the center. Usually too large to work on today’s computers, the UB-led team was able to shrink the vortex laser to the point where it is compatible with computer chips. Because the laser beam travels in a cork­screw pattern, encoding information into different vortex twists, it’s able to carry 10 times or more the amount of information than that of con­ventional lasers, which move linearly. The vortex laser is one component of many, such as advanced trans­mitters and receivers, which will ulti­mately be needed to continue building more powerful computers and data­centers. (Source: U Buffalo)

Reference: P. Miao et al.: Orbital angular momentum microlaser, Science 353, 464 (2016); DOI: 10.1126/science.aaf8533

Link: Integrated Photonics Lab, Dept. of Electrical Engineering at the University at Buffalo, USA

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