Researchers at the Massachusetts Institute of Technology (MIT) and MIT Lincoln Laboratory have demonstrated a new cooling technique for chip-based trapped-ion quantum computers, achieving speeds and efficiencies significantly beyond conventional laser cooling methods.
The team implemented polarization-gradient cooling using a photonic chip equipped with precisely engineered nanoscale antennas. This approach reduced ion temperature to nearly ten times below the Doppler limit and achieved cooling in about 100 microseconds—several times faster than previous methods.
The photonic chip emits tightly focused, intersecting beams of light with different polarizations, forming a stable vortex that reduces ion vibrations. These beams are generated by antennas integrated into the chip and connected through optical waveguides that ensure precise light routing and pattern stability.
The cooling technique addresses a major challenge in scaling trapped-ion quantum computers. Traditional systems rely on bulky external optics to manipulate a small number of ions, limiting scalability. In contrast, integrated-photonics-based systems enable compact architectures with thousands of sites on a single chip.
“This work opens the door to a variety of advanced operations for trapped ions that weren’t previously attainable, even beyond efficient ion cooling,” said Jelena Notaros, senior author and associate professor of Electrical Engineering and Computer Science at MIT.
The results were published in Light: Science and Applications and Physical Review Letters. The researchers plan to expand the technique to multiple ions and explore further applications using stable, chip-generated light beams.
