Researchers create a super-efficient Ti:sapphire laser that fits on a chip

Researchers have achieved a potentially groundbreaking innovation in laser technology by developing a titanium-sapphire (Ti:sapphire) laser on a chip. This new prototype is dramatically smaller, more efficient, and less expensive than its predecessors, marking a significant leap forward with a technology that has broad applications in industry, medicine, and beyond.

Ti:sapphire lasers are known for their unmatched performance in quantum optics, spectroscopy, and neuroscience due to their wide gain bandwidth and ultrafast light pulses. However, their bulky size and high cost have limited their widespread adoption. Traditional Ti:sapphire lasers occupy cubic feet in volume and can cost hundreds of thousands of dollars, in addition to requiring high-powered lasers costing $30,000 each to feed it the energy it needs to operate.

The new chip-scale Ti:sapphire laser, developed by a team led by Jelena Vučković, a professor of electrical engineering at Stanford University, addresses these limitations. Published in the journal Nature , the study reveals that the prototype is 10,000 times smaller and 1,000 times cheaper than conventional Ti:sapphire lasers.

“This is a complete departure from the old model,” Vučković said in a Stanford University news release . “Instead of one large and expensive laser, any lab might soon have hundreds of these valuable lasers on a single chip. And you can fuel it all with a green laser pointer.”

Etching the laser into a nanometers-thin chip

Joshua Yang, a doctoral candidate and co-first author of the study, highlighted the transformative potential of this innovation. “When you leap from tabletop size and make something producible on a chip at such a low cost, it puts these powerful lasers in reach for a lot of different important applications,” Yang said.

The team crafted the new laser by starting with a bulk layer of titanium-sapphire on a silicon dioxide platform atop a sapphire crystal. They then processed this into a layer only a few hundred nanometers thin, and patterned it with tiny ridges acting as waveguides to intensify the light. The addition of a microscale heater allows tuning of the emitted light’s wavelength, ranging from 700 to 1,000 nanometers.

The chip-scale Ti:sapphire laser has the potential to revolutionize multiple fields. In quantum physics, it could scale down quantum computers. In neuroscience, it might enable more compact optogenetics probes. In ophthalmology, it could advance laser surgery and retinal assessments.

The research team is now focusing on perfecting the laser and exploring mass production methods. Yang is also working on bringing the technology to market. “We could put thousands of lasers on a single 4-inch wafer,” Yang said. “That’s when the cost per laser starts to become almost zero. That’s pretty exciting.”