An ultra-thin invention could make future computing, sensing and coding technologies noticeably smaller and more powerful by helping scientists control a strange but useful phenomenon for quantum mechanics, according to new research recently published in the journal. Sciences.
Scientists at Sandia National Laboratories and the Max Planck Institute for the Science of Light report a device that can replace a room full of equipment to correlate photons with a strange quantum effect called entanglement. This device — a type of nano-designed material called a supersurface — paves the way for photons that are entangled in complex ways that weren’t possible with embedded technologies.
When scientists say that photons are entangled, they mean that they are connected in a way that affects one on the other, no matter where or how far apart the photons are in the universe. It’s the effect of quantum mechanics, the laws of physics that govern particles and very small things.
Although this phenomenon may seem strange, scientists have harnessed it to process information in new ways. For example, entanglement helps protect accurate quantum information and correct errors in quantum computing, an area that could one day have sweeping effects in national security, science, and finance. Interlacing also enables new and advanced encryption methods for secure communication.
The research for the pioneering device, which is 100 times thinner than a paper, was conducted in part at the Center for Integrated Nanotechnology, a Department of Energy Office of Science user facility operated by Sandia and Los Alamos National Laboratories. The Sandia team received funding from the Office of Science, Basic Energy Sciences Program.
Light enters, entangled photons come out
The new super-interface serves as an input to this unusual quantum phenomenon. In some ways, it resembles the mirror in Lewis Carroll’s Through the Looking-Glass, in which the young protagonist Alice experiences a new and strange world.
Instead of passing through their new device, the scientists shine a laser beam through it. The beam of light passes through an extremely thin sample of glass covered with nanostructures made of a common semiconductor material called gallium arsenide.
“It disturbs all optical fields,” said Yigal Brenner, Sandia’s chief scientist and expert in a field called nonlinear optics who led the Sandia team. Sometimes, he said, a pair of entangled photons at different wavelengths would appear from the sample in the same direction as the incoming laser beam.
Brenner said he’s excited about the device because it’s designed to produce complex networks of entangled photons — not just one pair at a time, but several pairs all entangled together, some indistinguishable from one another. Some technologies need these complex types of so-called multi-entanglement of complex information processing schemes.
Other miniaturization techniques based on silicon photons can also entangle photons but without the much-needed level of complex and multiple entanglement. Until now, the only way to achieve such results has been to use multiple tables filled with lasers, specialized crystals, and other optical equipment.
“It’s very complex and difficult to solve when this multiple entanglement needs more than two or three pairs,” Brenner said. “These nonlinear metasurfaces essentially achieve this task in a single sample when, before, incredibly complex optical settings were required.”
The scientific paper shows how the team successfully tuned their metasurface to produce entangled photons of varying wavelengths, a crucial precursor to the generation of multiple pairs of intricately entangled photons simultaneously.
However, the researchers note in their paper that the efficiency of their devices – the rate at which they can generate groups of entangled photons – is lower than other techniques and needs improvement.
What is a superficial surface?
A metasurface is a synthetic material that interacts with light and other electromagnetic waves in ways that conventional materials cannot. Brenner said commercial industries are busy developing surfaces because they take up less space and can do more with light than, say, traditional lenses.
“You can now replace thick lenses and optical elements with piercing surfaces,” Brenner said. “These kinds of hacking surfaces are going to revolutionize consumer products.”
Sandia is one of the world’s leading institutions conducting research into metasurfaces and metamaterials. Between the Systems Engineering, Microscience, and Applications complex, which manufactures composite semiconductors, and the nearby center for integrated nanotechnologies, researchers have access to all the specialized tools they need to design, manufacture and analyze these ambitious new materials.
“The work was challenging because it required a micro-nanofabrication technique to obtain the sharp, narrow optical resonances that seed the quantum process of work,” said Silvan Gennaro, a former postdoctoral researcher at Sandia who has worked on several aspects of the project.
The device was designed, manufactured and tested through a partnership between Sandia and a research group led by physicist Maria Chekhova, an expert in quantum entanglement of photons at the Max Planck Institute for the Science of Light.
“Surface surfaces are leading to a paradigm shift in quantum optics, combining ultra-small sources of quantum light with the far-reaching possibilities of quantum state engineering,” said Thomas Santiago Cruz, a member of the Max Planck team and first author on the paper.
This latest research could spark a second revolution — one that sees metamaterials developed not just as a new type of lens, but as a technology for quantum information processing and other new technologies, said Brenner, who has studied metamaterials for more than a decade. Applications.
“There has been one wave with already well-established metasurfaces on its way,” he said. “Maybe a second wave of innovative applications is coming.”
Sandia National Laboratories is a multi-function laboratory operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. of the US Department of Energy’s National Nuclear Security Administration. Sandia Labs has primary research and development responsibilities in the areas of nuclear deterrence, global security, defense, energy technologies, and economic competitiveness, with major facilities in Albuquerque, New Mexico and Livermore, California.