If two recent studies using some novel applications around the unique properties of light are any indication, we may be about to enter a brand-new era of data and communication. Limits on storage, data transfer, and information-sharing speed may simply vanish.
The first study in nature photonics—around the ability to encrypt data in "twisted light" that's sent across an open vacuum and then received at the other end—set the technology world buzzing. Such twisted light research is beginning to show that data can be transmitted using photons generated in an infinite array of orbital angular momentum shapes.
But a more recent study in nature communication—on the ability to use a laser beam of light to control the spin of the electrons in an atom's nucleus, opening the possibility that data could be shared in a quantum state once the electron spin is essentially stabilized—was hardly noticed even though its applications could be truly revolutionary.
For the study, researchers from the City College of New York and the University of California-Berkeley developed a technique using laser light to pattern the alignment of spin within atoms so that the pattern can be rewritten on the fly—in effect, creating the possibility of rewritable spintronic circuits.
Even though newly discovered techniques and technology double computing processing speed on a predictable basis—which computer scientists refer to as "Moore's law"—we may be approaching the upper limits for computer processing speeds using existing digital technology and electronic circuits.
Because all current electronic devices (laptops, cellphones, etc.) use circuits with elaborate and ever-smaller patterns etched into them in order to translate electrical charges as zeros and ones in binary code, researchers have long predicted that we would eventually reach a limit for the amount of data transfers on such integrated circuits.
"Once the chip is printed, it can only be used one way," said one of the researchers, Berkeley chemical and bimolecular engineering professor Jeffrey Reimer. And that pattern is finite.
Quantum computing, on the other hand, would not have these sorts of upper limits. That's why the CCNY and Berkeley research is so intriguing—it creates a possible path forward for actual quantum computing.
Previous quantum studies have already shown that data can be simultaneously transferred from one location to another using entangled electrons. But electrons spin and switch back and forth rapidly, randomly and unpredictably, making them rather unstable as systems to store or transmit data and information.
The CCNY and Berkeley researchers solved this problem by using laser beams of light to stabilize the spins of the electrons. They illuminated a sample of gallium arsenide (the same semiconductor used in cellphone chips) with a laser light pattern and aligned the spins of all the atomic nuclei, including their electrons. This suppressed the random "back and forth" switching of the electrons, which would in turn form the basis of a future spintronic circuit.
"What you could have is a chip you can erase and rewrite on the fly with just the use of a light beam," said a second research co-author, CCNY physics professor Carlos Meniles. "If you can actually rewrite with a beam of light and alter this pattern, you can make the circuit morph to adapt to different requirements. Imagine what you can make a system like that do for you."
Meanwhile, the "twisted light" research, the result of a multinational team effort led by the University of Southern California, could have near-term implications. The research showed that a twisted light system could transmit data up to 2.56 terabits per second. To put this in perspective, broadband cable supports up to 30 megabits per second, making a twisted light system 85,000 times faster.
"You're able to do things with light that you can't do with electricity," said one of the lead researchers, USC engineering professor Alan Willner. "That's the beauty of light. It's a bunch of photons that can be manipulated in many different ways at very high speed."
The researchers studied the orbital angular momentum of photons, or the rotation of the photon around its direction of momentum. They then studied whether data could be stored and transmitted over the space of a meter in up to eight different permutations of photons traveling in a helical pattern.
Willner and research teams in China, Pakistan, Israel, and the United States used beam-twisting "phase holograms" to manipulate eight beams of light so that each one twisted into a different DNA-like helical shape in free space. Each of the eight had its own individual twist that could be encoded with zero and one data bit streams.
The simplest way to think of the USC twisted light research is to imagine a slinky. If you hold one end of the slinky and a second person pulls the slinky apart from the other end, that's one possible version of the way a photon travels. Now, take a step closer. That's a second possibility. As you move the slinky closer or farther apart, there are endless variations of such angular orbital momentum of the photons—all of which could be used to store and transmit data.
The researchers displayed the various twisted light options in their paper—all of which could be transmitted simultaneously from one location to another without competing.
There are any number of roadblocks keeping this research from immediately translating into commercial use, not the least of which is that it generally works only in empty space. But the next steps in this research field will look at how such twisted light systems could, in fact, be adapted for use in fiber optics and ultimately in data transmission over the Internet and between open-air mobile devices.
These two recent studies perfectly illustrate why computer science researchers see limitless possibilities for the future of information systems. Albert Einstein may have proven that there's a speed limit for objects—the speed of light—but researchers are beginning to show that the ways in which we can manipulate light for other purposes may be endless.