Home > Press > Rice-sized laser, powered one electron at a time, bodes well for quantum computing
![]() |
Princeton University researchers have built a rice grain-sized microwave laser.
CREDIT: Jason Petta, Princeton University |
Abstract:
Princeton University researchers have built a rice grain-sized laser powered by single electrons tunneling through artificial atoms known as quantum dots. The tiny microwave laser, or "maser," is a demonstration of the fundamental interactions between light and moving electrons.
The researchers built the device -- which uses about one-billionth the electric current needed to power a hair dryer -- while exploring how to use quantum dots, which are bits of semiconductor material that act like single atoms, as components for quantum computers.
"It is basically as small as you can go with these single-electron devices," said Jason Petta, an associate professor of physics at Princeton who led the study, which was published in the journal Science.
The device demonstrates a major step forward for efforts to build quantum-computing systems out of semiconductor materials, according to co-author and collaborator Jacob Taylor, an adjunct assistant professor at the Joint Quantum Institute, University of Maryland-National Institute of Standards and Technology. "I consider this to be a really important result for our long-term goal, which is entanglement between quantum bits in semiconductor-based devices," Taylor said.
The original aim of the project was not to build a maser, but to explore how to use double quantum dots -- which are two quantum dots joined together -- as quantum bits, or qubits, the basic units of information in quantum computers.
"The goal was to get the double quantum dots to communicate with each other," said Yinyu Liu, a physics graduate student in Petta's lab. The team also included graduate student Jiri Stehlik and associate research scholar Christopher Eichler in Princeton's Department of Physics, as well as postdoctoral researcher Michael Gullans of the Joint Quantum Institute.
Because quantum dots can communicate through the entanglement of light particles, or photons, the researchers designed dots that emit photons when single electrons leap from a higher energy level to a lower energy level to cross the double dot.
Each double quantum dot can only transfer one electron at a time, Petta explained. "It is like a line of people crossing a wide stream by leaping onto a rock so small that it can only hold one person," he said. "They are forced to cross the stream one at a time. These double quantum dots are zero-dimensional as far as the electrons are concerned -- they are trapped in all three spatial dimensions."
The researchers fabricated the double quantum dots from extremely thin nanowires (about 50 nanometers, or a billionth of a meter, in diameter) made of a semiconductor material called indium arsenide. They patterned the indium arsenide wires over other even smaller metal wires that act as gate electrodes, which control the energy levels in the dots.
To construct the maser, they placed the two double dots about 6 millimeters apart in a cavity made of a superconducting material, niobium, which requires a temperature near absolute zero, around minus 459 degrees Fahrenheit. "This is the first time that the team at Princeton has demonstrated that there is a connection between two double quantum dots separated by nearly a centimeter, a substantial distance," Taylor said.
When the device was switched on, electrons flowed single-file through each double quantum dot, causing them to emit photons in the microwave region of the spectrum. These photons then bounced off mirrors at each end of the cavity to build into a coherent beam of microwave light.
One advantage of the new maser is that the energy levels inside the dots can be fine-tuned to produce light at other frequencies, which cannot be done with other semiconductor lasers in which the frequency is fixed during manufacturing, Petta said. The larger the energy difference between the two levels, the higher the frequency of light emitted.
Claire Gmachl, who was not involved in the research and is Princeton's Eugene Higgins Professor of Electrical Engineering and a pioneer in the field of semiconductor lasers, said that because lasers, masers and other forms of coherent light sources are used in communications, sensing, medicine and many other aspects of modern life, the study is an important one.
"In this paper the researchers dig down deep into the fundamental interaction between light and the moving electron," Gmachl said. "The double quantum dot allows them full control over the motion of even a single electron, and in return they show how the coherent microwave field is created and amplified. Learning to control these fundamental light-matter interaction processes will help in the future development of light sources."
###
The paper, "Semiconductor double quantum dot micromaser," was published in the journal Science on Jan. 16, 2015. The research was supported by the David and Lucile Packard Foundation, the National Science Foundation (DMR-1409556 and DMR-1420541), the Defense Advanced Research Projects Agency QuEST (HR0011-09-1-0007), and the Army Research Office (W911NF-08-1-0189).
####
For more information, please click here
Contacts:
Catherine Zandonella
609-258-0541
Copyright © Princeton 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 News Press |
News and information
Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025
Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025
A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025
Wireless/telecommunications/RF/Antennas/Microwaves
HKUST researchers develop new integration technique for efficient coupling of III-V and silicon February 16th, 2024
Researchers demonstrate co-propagation of quantum and classical signals: Study shows that quantum encryption can be implemented in existing fiber networks January 20th, 2023
Chip Technology
A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025
Programmable electron-induced color router array May 14th, 2025
Enhancing power factor of p- and n-type single-walled carbon nanotubes April 25th, 2025
Ultrafast plasmon-enhanced magnetic bit switching at the nanoscale April 25th, 2025
Nanomedicine
Ben-Gurion University of the Negev researchers several steps closer to harnessing patient's own T-cells to fight off cancer June 6th, 2025
Cambridge chemists discover simple way to build bigger molecules – one carbon at a time June 6th, 2025
Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025
Self-propelled protein-based nanomotors for enhanced cancer therapy by inducing ferroptosis June 6th, 2025
Quantum Computing
Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025
Magnetism in new exotic material opens the way for robust quantum computers June 4th, 2025
Programmable electron-induced color router array May 14th, 2025
Sensors
Quantum engineers ‘squeeze’ laser frequency combs to make more sensitive gas sensors January 17th, 2025
Nanotechnology: Flexible biosensors with modular design November 8th, 2024
Nanoelectronics
Interdisciplinary: Rice team tackles the future of semiconductors Multiferroics could be the key to ultralow-energy computing October 6th, 2023
Key element for a scalable quantum computer: Physicists from Forschungszentrum Jülich and RWTH Aachen University demonstrate electron transport on a quantum chip September 23rd, 2022
Reduced power consumption in semiconductor devices September 23rd, 2022
Atomic level deposition to extend Moore’s law and beyond July 15th, 2022
Announcements
Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025
Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025
A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025
Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters
Cambridge chemists discover simple way to build bigger molecules – one carbon at a time June 6th, 2025
Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025
Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025
A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025
Quantum Dots/Rods
A new kind of magnetism November 17th, 2023
IOP Publishing celebrates World Quantum Day with the announcement of a special quantum collection and the winners of two prestigious quantum awards April 14th, 2023
Qubits on strong stimulants: Researchers find ways to improve the storage time of quantum information in a spin rich material January 27th, 2023
NIST’s grid of quantum islands could reveal secrets for powerful technologies November 18th, 2022
Photonics/Optics/Lasers
Institute for Nanoscience hosts annual proposal planning meeting May 16th, 2025
Programmable electron-induced color router array May 14th, 2025
![]() |
||
![]() |
||
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 |
||
![]() |