Home > Press > 'Exceptional' research points way toward quantum discoveries: Rice University scientists make tunable light-matter couplings in nanotube films
Rice University scientists used nanotube films and polarized light to strongly couple light and matter progressively and on demand at room temperature. Their discovery of exceptional points in the resulting polaritons could allow researchers to explore novel quantum technologies like advanced information storage or one-dimensional lasers. (Credit: Weilu Gao/Rice University) |
Abstract:
Rice University scientists are known for exceptional research, but a new paper led by physicist Junichiro Kono makes that point most literally.
The discovery of exceptional points in a unique material created by Kono’s lab is one of several revelations in a paper that appears in Nature Photonics.
These spectral singularities are central to another phenomenon, the team's newfound ability to continuously tune the transition between the weak and ultra-strong coupling of light and matter confined in a vacuum. That ability may give researchers the opportunity to explore novel quantum technologies like advanced information storage or one-dimensional lasers.
Kono and his colleagues have expertise in corralling photons and excitons (bound electron-hole pairs) in solids to form condensed matter in a quantum well. They reported on their ability to do so by manipulating electrons with light and a magnetic field in 2016.
In the same year, they announced their ability to make highly aligned, wafer-sized films of single-walled carbon nanotubes.
In the new work, Kono and Rice postdoctoral researcher and lead author Weilu Gao combined techniques from the earlier papers and used polarized light to trigger the formation of quasiparticles known as polaritons – strongly coupled light and matter – inside the one-dimensional nanotubes in a cavity at room temperature.
Because polaritons can only resonate along the aligned nanotubes' length, they appear when incoming light is polarized in the same direction. When turned 90 degrees, the polaritons disappear progressively.
The polarization angle at which polaritons appear and disappear is known as the exceptional point, and neither Kono nor Gao considered it important until a theorist friend stepped in.
"Discovering the point was important, and surprising," Kono said. "In our first version of the paper, we didn't really emphasize it. But while it was under review, we showed a theorist the data and he pointed out, 'You have this Dirac point-like feature here.' We started to look at it more carefully, and indeed there was an exceptional point."
Dirac points are a characteristic of graphene; they appear where the material's conduction and valence bands connect to make it a perfect conductor of electricity. In semiconductor materials, the energetic separation between bands determines the material's band gap.
Exceptional points have been studied in other contexts; in recent experiments, scientists showed light itself could be slowed or stopped at just such a point.
"A lot of the anomalous properties of electrons in graphene are related to the existence of this special point, called the Dirac point, or energy-zero point," Kono said. "Graphene's band structure is completely untraditional compared with solid semiconductors like gallium arsenide or silicon, which have conduction and valence bands that define their band gap.
"In our case, we have a kind of band gap between the upper and lower polaritons when polarized light is parallel to the films, but turning the light polarization changes everything. When you hit the exceptional point, the band gap closes and polaritons disappear."
Kono said the work also demonstrates that the aligned nanotubes cooperate with each other. "The vacuum Rabi splitting (a measure of coupling strength between photons in the vacuum and electrons in the solid film) increases as we increase the number of nanotubes," he said. "This is evidence that the nanotubes coherently cooperate as they interact with the cavity photons."
Gao said the Rice experiment suggested a way might be found to create photons – elemental particles of light – from a vacuum. That could be important for quantum-level storage as a way to extract data from qubits.
"There are theoretical proposals for converting virtual photons into real photons, sometimes called Casimir photons," Kono said. "We could have matter inside a cavity interacting with the vacuum, and when we trigger the system somehow we destroy the coupling, and suddenly photons come out. That's an experiment we want to do, because producing photons on demand from a vacuum would be cool."
Co-authors of the paper are Rice graduate student Xinwei Li and Motoaki Bamba, an associate professor at Osaka University. Kono is a professor of electrical and computer engineering, of physics and astronomy, and of materials science and nanoengineering.
The Department of Energy Basic Energy Science Office, the National Science Foundation, the Robert A. Welch Foundation, the PRESTO program of the Japan Science and Technology Agency and the ImPACT program of the Government of Japan’s Council for Science, Technology and Innovation supported the research.
####
About Rice University
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation’s top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,970 undergraduates and 2,934 graduate students, Rice’s undergraduate student-to-faculty ratio is just under 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for quality of life and for lots of race/class interaction and No. 2 for happiest students by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger’s Personal Finance. To read “What they’re saying about Rice,” go to http://tinyurl.com/RiceUniversityoverview .
Follow Rice News and Media Relations via Twitter @RiceUNews
For more information, please click here
Contacts:
David Ruth
713-348-6327
Mike Williams
713-348-6728
Copyright © Rice University
If you have a comment, please Contact us.Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Related Links |
Rice Department of Electrical and Computer Engineering:
Rice Department of Physics and Astronomy:
Rice Department of Materials Science and NanoEngineering:
Related News Press |
Quantum Physics
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
News and information
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Graphene/ Graphite
NRL discovers two-dimensional waveguides February 16th, 2024
Govt.-Legislation/Regulation/Funding/Policy
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Chemical reactions can scramble quantum information as well as black holes April 5th, 2024
Possible Futures
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
With VECSELs towards the quantum internet Fraunhofer: IAF achieves record output power with VECSEL for quantum frequency converters April 5th, 2024
Chip Technology
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Utilizing palladium for addressing contact issues of buried oxide thin film transistors April 5th, 2024
HKUST researchers develop new integration technique for efficient coupling of III-V and silicon February 16th, 2024
Nanotubes/Buckyballs/Fullerenes/Nanorods/Nanostrings
Tests find no free-standing nanotubes released from tire tread wear September 8th, 2023
Detection of bacteria and viruses with fluorescent nanotubes July 21st, 2023
Optical computing/Photonic computing
With VECSELs towards the quantum internet Fraunhofer: IAF achieves record output power with VECSEL for quantum frequency converters April 5th, 2024
Chemical reactions can scramble quantum information as well as black holes April 5th, 2024
Optically trapped quantum droplets of light can bind together to form macroscopic complexes March 8th, 2024
HKUST researchers develop new integration technique for efficient coupling of III-V and silicon February 16th, 2024
Discoveries
Chemical reactions can scramble quantum information as well as black holes April 5th, 2024
New micromaterial releases nanoparticles that selectively destroy cancer cells April 5th, 2024
Utilizing palladium for addressing contact issues of buried oxide thin film transistors April 5th, 2024
Materials/Metamaterials/Magnetoresistance
Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024
Focused ion beam technology: A single tool for a wide range of applications January 12th, 2024
Announcements
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Grants/Sponsored Research/Awards/Scholarships/Gifts/Contests/Honors/Records
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Chemical reactions can scramble quantum information as well as black holes April 5th, 2024
Photonics/Optics/Lasers
With VECSELs towards the quantum internet Fraunhofer: IAF achieves record output power with VECSEL for quantum frequency converters April 5th, 2024
Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024
Optically trapped quantum droplets of light can bind together to form macroscopic complexes March 8th, 2024
HKUST researchers develop new integration technique for efficient coupling of III-V and silicon February 16th, 2024
Research partnerships
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Researchers’ approach may protect quantum computers from attacks March 8th, 2024
'Sudden death' of quantum fluctuations defies current theories of superconductivity: Study challenges the conventional wisdom of superconducting quantum transitions January 12th, 2024
Quantum nanoscience
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
Optically trapped quantum droplets of light can bind together to form macroscopic complexes March 8th, 2024
Bridging light and electrons January 12th, 2024
'Sudden death' of quantum fluctuations defies current theories of superconductivity: Study challenges the conventional wisdom of superconducting quantum transitions January 12th, 2024
The latest news from around the world, FREE | ||
Premium Products | ||
Only the news you want to read!
Learn More |
||
Full-service, expert consulting
Learn More |
||