Researchers have achieved a significant step forward in quantum computing by developing a device that is almost 100 times thinner than the width of a human hair. The work, published in the journal Nature Communications, introduces a new type of optical phase modulator designed to precisely control laser light. This capability is essential for running future quantum computers that may rely on thousands or even millions of qubits -- the fundamental units used to store and process quantum information.
Just as important as its size is how the device is made. Instead of relying on custom-built laboratory equipment, the researchers used scalable manufacturing methods similar to those that produce the processors found in computers, smartphones, vehicles, and household appliances -- essentially any technology powered by electricity (even toasters). This approach makes the device far more practical to produce in large numbers.
A Tiny Device Built for Real-World Scale
The research was led by Jake Freedman, an incoming PhD student in the Department of Electrical, Computer and Energy Engineering, alongside Matt Eichenfield, professor and Karl Gustafson Endowed Chair in Quantum Engineering. The team also collaborated with scientists from Sandia National Laboratories, including co-senior author Nils Otterstrom. Together, they created a device that combines small size, high performance, and low cost, making it suitable for mass production.
At the heart of the technology are microwave-frequency vibrations that oscillate billions of times per second. These vibrations allow the chip to manipulate laser light with remarkable precision.
By directly controlling the phase of a laser beam, the device can generate new laser frequencies that are both stable and efficient. This level of control is a key requirement not only for quantum computing, but also for emerging fields such as quantum sensing and quantum networking.
Why Quantum Computers Need Ultra-Precise Lasers
Some of the most promising quantum computing designs use trapped ions or trapped neutral atoms to store information. In these systems, each atom acts as a qubit. Researchers interact with these atoms by directing carefully tuned laser beams at them, effectively giving instructions that allow calculations to take place. For this to work, each laser must be adjusted with extreme precision, sometimes to within billionths of a percent.
"Creating new copies of a laser with very exact differences in frequency is one of the most important tools for working with atom- and ion-based quantum computers," Freedman said. "But to do that at scale, you need technology that can efficiently generate those new frequencies."
Currently, these precise frequency shifts are produced using large, table-top devices that require substantial microwave power. While effective for small experiments, these systems are impractical for the massive number of optical channels needed in future quantum computers.
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