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MIT researchers have discovered that novel photovoltaic nanoparticles can emit streams of identical photons, potentially paving the way for new quantum computing technologies and quantum teleportation devices.
The device emits a stream of single photons and could provide a basis for optical quantum computers.
Using novel materials that have been widely studied as potential new solar photovoltaics, researchers at
While the work is currently a fundamental discovery of these materials’ capabilities, it might ultimately pave the way to new optically based quantum computers, as well as possible quantum teleportation devices for communication, the researchers say. The results were published on June 22 in the journal
Microscopic imaging shows the size uniformity of the perovskite nanocrystals. Credit: Courtesy of the researchers
Most concepts for
“With these qubit-like photons,” Kaplan explains, “with just ‘household’ linear optics, you can build a quantum computer, provided you have appropriately prepared photons.”
The preparation of those photons is the key thing. Each
The source they ended up using is a form of lead-halite perovskite nanoparticles. Thin films of lead-halide perovskites are being widely pursued as potential next-generation photovoltaics, among other things, because they could be much more lightweight and easier to process than today’s standard silicon-based photovoltaics. In nanoparticle form, lead-halide perovskites are notable for their blindingly fast cryogenic radiative rate, which sets them apart from other colloidal semiconductor nanoparticles. The faster the light is emitted, the more likely the output will have a well-defined wavefunction. The fast radiative rates thus uniquely position lead-halide perovskite nanoparticles to emit quantum light.
To test that the photons they generate really do have this indistinguishable property, a standard test is to detect a specific kind of interference between two photons, known as Hong-Ou-Mandel interference. This phenomenon is central to a lot of quantum-based technologies, Kaplan says, and therefore demonstrating its presence “has been a hallmark for confirming that a photon source can be used for these purposes.”
Very few materials can emit light that meets this test, he says. “They pretty much can be listed on one hand.” While their new source is not yet perfect, producing the HOM interference only about half the time, the other sources have significant issues with achieving scalability. “The reason other sources are coherent is they’re made with the purest materials, and they’re made individually one by one,
So, even though these materials may not yet be perfect, “They’re very scalable, we can make a lot of them. and they’re currently very unoptimized. We can integrate them into devices, and we can further improve them,” Kaplan says.
At this stage, he says, this work is “a very interesting fundamental discovery,” showing the capabilities of these materials. “The importance of the work is that hopefully, it can encourage people to look into how to further enhance these in various device architectures.”
And, Bawendi adds, by integrating these emitters into reflective systems called optical cavities, as has already been done with the other sources, “we have full confidence that integrating them into an optical cavity will bring their properties up to the level of the competition.”
Reference: “Hong–Ou–Mandel interference in colloidal CsPbBr3 perovskite nanocrystals” by Alexander E. K. Kaplan, Chantalle J. Krajewska, Andrew H. Proppe, Weiwei Sun, Tara Sverko, David B. Berkinsky, Hendrik Utzat and Moungi G. Bawendi, 22 June 2023, Nature Photonics.
DOI: 10.1038/s41566-023-01225-w
The research team included Chantalle Krajewska, Andrew Proppe, Weiwei Sun, Tara Sverko, David Berkinsky, and Hendrik Utzat. The work was supported by the U.S. Department of Energy and the Natural Sciences and Engineering Research Council of Canada.