Honda Research Institute USA Scientists Achieve Breakthrough in Quantum Materials with Potential to Enhance Communication Security

• New "nanoribbon" material just a single-atom thick and tens of atom wide enables secure quantum communication for sending sensitive information
• When excited by a laser, nanoribbon material emits light that can carry encoded information to create a physical layer of quantum secure communication that immediately detects any attempt to intercept the communications
• Breakthrough builds upon HRI's previous quantum research on width-controllable growth of double-atom thick nanoribbons

TORRANCE, Calif., Jan. 28, 2025 /PRNewswire/ -- Scientists at Honda Research Institute USA, Inc. (HRI-US) have made a significant breakthrough in the fields of quantum materials and quantum communications by developing a novel method for growing atomically thin "nanoribbons" – one atom thick and tens of atoms-wide ribbon-shaped materials – enabling unbreakable secure communication of sensitive information.

Detailed in the journal Nature Communications, this innovative technology allows for precise control over the thickness and width of transition metal dichalcogenides nanoribbons (NR), and their electronic properties, which is essential for their application in advanced quantum optoelectronics.

"Our technology provides a new pathway for the synthesis of quantum nanoribbons with precise width control, leveraging their unique mechanical and electronic properties as a single photon light source to realize secure communication known as 'quantum communication'," said Dr. Avetik Harutyunyan, Senior Chief Scientist, Honda Research Institute USA Inc. and the leader of the quantum research.

Secure communications based on quantum key distribution (QKD) method leverages the principles of quantum mechanics to protect the information. QKD method relies on the secure distribution of encryption keys between two parties, allowing them to generate a shared secret key that can be used to encrypt and decrypt sensitive information. Any attempt to intercept the encrypted communications will be immediately detected as it would physically interfere with the transmission of the information.

HRI researchers and university collaborators were able to encode the information on a stream of individual photons– "atoms" of light or elementary particles of the light – emitted by the new nanoribbon material, similar to the use of binary code of "0's" and "1's" used in computing. The stream of photons can then be used to create and distribute the information between a communicating transmitter and receiver. In this scheme, the transmitter sends a series of single photons in one of two possible quantum states, and the receiver then performs a measurement that differentiates between these states. After comparing the transmitted and measured quantum states of the photons, the sender and the receiver can establish a secure key that can be used for encryption of their communication. Any attempt to eavesdrop on the communication will inevitably interfere with the quantum states, introducing errors that can be immediately detected by the sender and the receiver. 

Regulating the stream of single photons is essential to this process. Laser-based photon sources currently in use produce photons that are too dense (e.g. 7.5 x10²⁰ photons per pulse) for this scheme to work without interfering with encoded information, creating the need for a single photon emitter source that provides the stream of single photons used to encode the information.

"By creating a single atomic-layer NR from materials such as molybdenum disulfide (MoS2) and tungsten diselenide (WSe2) using transition metal-alloyed nanoparticles as a catalyst that initiate the growth of nanoribbons, we were able to control the width of the NRs during the growth process down to 7 nanometers," said Dr. Xufan Li Principial Scientist at HRI-US.   

The resulting 1-dimensional NR material was transferred over the sharp tip of a cone-shape probe by a transfer process developed by Dr. Shuang Wu, Senior Scientist at HRI-US, which creates a strain-induced unique electronic structure that is localized on the tip of the cone. Under the laser beam excitation, the strain-engineered electronic structure on the tip of the probe caused the emission of a stream of single photons.

"Our new nanoribbons exhibit remarkable width-dependent and strain-induced electronic properties and quantum emission characteristics, including up to 90% purity of single photons in the stream," said Harutyunyan. "In subsequent research with collaborators, we were able to further improve the photon purity higher than 95%, making the material highly promising for future applications in quantum communication and quantum optoelectronic devices."

HRI collaborated with Professor Nicholas Borys of Montana State University and Professor James Schuck Columbia University to validate the feasibility of the new materials as a single photon emitter source for quantum communication. The research was completed with contributions from multiple researchers and organizations:

• Samuel Wyss, Joseph Stage, and Dr. Matthew Strasbourg of Montana State University
• Professor James Hone and Dr. Emanuil Yanev of Columbia University
• Professor Ju Li and Dr. Qing-Jie Li of Massachusetts Institute of Technology
• Dr. Yang Yang, Yongwen Sun and Yingxin Zhu of Pennsylvania State University
• Dr. Raymond R. Unocic of North Carolina State University

Previous research conducted by HRI on width-controllable growth of double atomic layer of nanoribbons appeared in Science Advances.

About Honda Research Institute USA
Honda Research Institute USA (HRI-US) conducts research to solve complex problems with direct application to the current and future Honda technology roadmap, including developing strategic partnerships with public and private institutions to foster innovation. HRI-US was founded in 2003 and is headquartered in Silicon Valley.  Learn more at http://usa.honda-ri.com/.

SOURCE Honda Research Institute USA, Inc.