Jason Petta: A microwave laser for quantum computing

Thursday, Nov 12, 2015

Invention A microwave laser for quantum computing

Inventor Jason Petta, Professor of Physics 

What it does The quantum-dot microwave laser, or “maser,” produces coherent microwave-frequency light and is powered by the one-by-one flow of single electrons. Its low power consumption, coupled with the ability to operate at extremely low temperatures, makes the maser useful for the creation of compact microwave amplifiers suitable for end-uses in chemical sensing and future quantum computing applications. 

The maser consists of two double quantum dots, which are small bits of semiconductor material that act like single atoms, placed at either ends of a microwave cavity. Unlike regular atoms, quantum dots can be connected to a battery that enables current to flow, causing the dots to emit photons that bounce off mirrors at each end of the cavity. The photons then build into a coherent beam of microwave light. 

The quantum dots are made from single-crystal indium arsenide nanowires just 50 nanometers in diameter that enable the isolation of single electrons in each double quantum dot. “This is basically as small as you can go with these single-electron devices,” Petta said. The maser uses about one-billionth of the electric current needed to power a hair dryer and works at temperatures near absolute zero, so it is ideal for quantum computing, which requires cryogenic temperatures. 

Another 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. 

Collaborators Graduate students Yinyu Liu and Jiri Stehlik, and associate research scholar Christopher Eichler in the Department of Physics; Jacob Taylor and Michael Gullans at the Joint Quantum Institute operated by the University of Maryland, the National Institute of Standards and Technology and the Laboratory for Physical Sciences. 

Development status Patent protection is pending. Princeton is seeking industrial interest for further development of this opportunity.

Funding sources The David and Lucile Packard Foundation, the National Science Foundation, the Defense Advanced Research Projects Agency’s QuEST (Quantum Entanglement Science and Technology) program, and the Army Research Office.