Penny-sized ultrafast laser could help self-driving cars see better and detect gravitational waves

A laser smaller than a penny has been created to measure objects at very fast rates. It switches its color millions of times faster than many standard systems, making it an interesting candidate for tasks that include guiding driverless cars and observing minute phenomena.

This chip-scale invention was developed by researchers at the University of Rochester and the University of California, Santa Barbara (UCSB).

It is part of a project led by Ph.D. student, Shixin Xue, under the guidance of Qiang Lin, the Dean’s Professor of electrical and computer engineering and optics at the University of Rochester.

They say this compact approach could replace large instruments that are often used for laser-based measurements, and will give more people access to precise testing tools.

Why miniaturization matters

A laser is a device that creates a narrow beam of light. Early lasers needed considerable space to operate. Modern ones can be quite small, but many still rely on bulky add-ons to keep them stable or adjust their color for certain tasks.

Researchers designed this new laser with lithium niobate, a synthetic material that uses the Pockels effect. This effect alters how light travels inside the material when an electric field is present.

The team looked for ways to switch the laser’s frequency at rates of about 10 quintillion times per second. That level of speed is linked to its ability to switch color so quickly.

The small footprint is a bonus. Having all these features on a chip smaller than a penny is appealing for scientists and engineers aiming to make new products and devices.

Laser measurement helps driverless cars

One of the clearest applications is LiDAR, which stands for light detection and ranging. LiDAR helps driverless cars map their surroundings by bouncing light beams off objects and measuring the reflections. 

“There are several applications we are aiming for that can already benefit from our designs,” said Xue. Many driverless cars already rely on basic LiDAR. Some are upgrading to frequency-modulated systems that need a wider range of color adjustments. 

To put their laser to the test, the group placed it in a miniature LiDAR setup. By rotating a simple disc and tracking reflected signals, they spotted letters built from small plastic blocks.

The setup is small, but they say it can scale to full-size driving conditions. The potential benefits include quick scans and precise detection of vehicles and objects on the road.

Detecting gravitational waves

Gravitational wave studies look for tiny ripples in the fabric of space. Facilities such as LIGO measure these waves with high-precision lasers that stretch across large areas.

The smaller laser could help those labs reduce equipment size or refine their measurements. Stability is key. By controlling the laser color so finely, even faint signals may be better spotted in future experiments.

“It’s a very important process that can be used for optical clocks that can measure time with extreme precision, but you need a lot of equipment to do that,” said Xue.

The new chip can integrate some of the parts that previously required separate devices. The frequency stability relies on another proven tool known as the Pound-Drever-Hall method, which locks the color of a laser to an external reference. 

Long-term device reliability

Prototypes need to show they can handle everyday realities: vibrations, temperature swings, and extended use. The group reports that their chip runs on standard electronics and can hold up under routine lab tests.

Early versions demonstrated a few hours of stable output. Better packaging might strengthen performance further. The team believes that in time, the device could maintain a steady signal for longer periods.

They also tested the device’s ability to limit noise. Noise is any signal that masks or distorts the desired reading. Traditional lasers can struggle with it, especially when very fine measurements matter.

The new laser, with a narrow linewidth around 167 Hz, kept random fluctuations relatively low. This helps with measurements where accuracy is critical.

Clocks, navigation, and laser measurement

Accurate distance measurement from laser systems is vital, but not just for autonomous vehicles. It is also helpful for drones, robots in factories, and robotics research. Improved sensors might lower the risk of collisions and make systems more efficient.

Better clocks, powered by stable lasers, may help in telecommunication where signals must sync up, or in research labs that track split-second changes in chemical reactions.

Various agencies helped fund this effort, including the Defense Advanced Research Projects Agency (DARPA) through its LUMOS program, as well as the National Science Foundation.

Their backing aids the push to refine designs, explore more compact layouts, and reduce manufacturing costs. Open sharing of results is planned, so other labs can build on the work.

Future of this fast, tiny laser

There is a growing trend toward integrated photonic devices for sensing and data transfer. Many hope to see large setups, like those in specialized labs, converted into small items that can be placed on a single chip.

If that happens, the cost and size of precision optical tools may come down significantly, letting more fields use them. This ranges from everyday consumer electronics to specialized industrial gear.

To make this chip-scale approach more robust, the researchers continue to refine waveguide designs and explore different ways to tune the laser’s frequency.

They are also keeping an eye on other specialized materials. By tuning how electrons move in these materials, it may be possible to further adjust the laser’s stability, range, and speed.

This ultrafast device demonstrates that precise measurement technology need not be bulky or expensive.

The work paves the way for future innovations where compact size and super-fast color changes could unlock faster scanning, better resolution, and simpler designs in fields that require accurate measurement.

The study is published in Light: Science & Applications.

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