Sandia, startup partner to make laser-cooled chips a reality

A startup backed by Sandia National Laboratories thinks it’s found a cool new way to keep the world’s supercomputers and datacenters cool enough to run efficiently: Zap ‘em with lasers.

Yes, we are aware that lasers often bring the heat when used in applications like welding, engraving, and blowing up Alderaan.

The startup has convinced Sandia National Laboratories and the University of New Mexico, both in the US, to help test-drive the idea of using lasers in combination with a “photonic cold plate” to cool chips.

Cold plates are highly conductive devices placed on components like CPUs and GPUs to draw away the heat they create while operating. Some cold plates use highly conductive materials. Others include pipes that carry a stream of liquid coolants that absorb heat and disperse it outside the datacenter.

Maxwell Labs proposes to make cold plates out of gallium arsenide, a material that in 2012 was found to cool down when zapped by lasers as the laser’s photons interact with the material’s atoms in weird and wonderful ways.

To produce cooling interactions gallium arsenide must be present in ultrapure, crystalline layers – because any impurities can absorb the laser energy and kill the cooling effect. Sandia is lending its expertise here, using molecular beam epitaxy to create ultra-thin layers, the lab wrote.

The molecular beam epitaxy reactor Sandia is using to build Maxwell’s photonic cooling plates – Click to enlarge

The finished cold plates will include miniscule features that channel laser light toward specific chip hotspots, to target areas that generate the most heat.

This micro-targeted laser cooling approach isn’t entirely new. As noted above, in 2012, a team at the University of Copenhagen used a laser to chill a nanoscale membrane down to -269°C. More recently, scientists at the University of Washington managed to cool water using similar techniques, hinting at the possibility of scaling laser refrigeration beyond the microscopic.

However, Maxwell isn’t trying to chase the macroscopic dream. Instead, it’s staying small – focusing on chip hotspots where laser cooling has the best chance of working.

“We really only have to cool down spots that are on the order of hundreds of microns,” said Sandia physicist Raktim Sarma, the lab’s lead on the project.

In addition to its cooling potential, Maxwell Labs says its photonic cooling system also enables energy reuse that isn’t possible with air or water cooling designs.

“We can reuse a ton of the waste heat of the processors to actually power the cooling systems and make them more efficient,” Maxwell Labs CEO and lead scientist Jacob Balma told The Register. Sandia further explained that extracted heat, in the form of light, could be recycled and turned back into electricity.

Still a lot of work to do

According to Sarma, Maxwell’s work could be the first attempt to apply photonic cooling to the datacenter workloads – and that means there’s a lot of work to do before the tech is ready for the commercial world.

Balma told us that this technique looks promising in simulations but is untested in the real world.

“Our claims are all based on advanced multi-physics modeling of the chip’s response to laser cooling on performance, temperature and power,” Balma said, adding that the biz is now in active testing, simulation, and fabrication work in cooperation with UNM and Sandia.

“Various components of the design have been validated, but the fully-integrated form factor work is on-going,” Balma told us.

And no, future datacenters aren’t going to be cooled entirely by lasers — that’s not exactly practical. While Balma didn’t give us hard numbers on the cost of operating a fully photonically cooled datacenters, he did admit that relying solely on laser light isn’t “the most cost-effective thing to do.”

“We don’t actually envision photonic cooling replacing existing cooling infrastructure, rather augmenting it to extend the limits of classical computing performance much further than it could otherwise go,” Balma said.

Used in a hybrid setup, laser cooling could lighten the thermal load on conventional systems and potentially lower overall energy use.

“Most customers would likely use fractional laser-cooling on top of existing air and liquid cooling systems,” Balma explained.

If all goes well, Maxwell Labs hopes to have a working demonstrator built by northern Autumn 2025.

Maxwell Labs says it’s been lining up early adopters for its still-unproven MXL-Gen1 Photonic Cooling system since last November. Balma expects to deliver systems to those customers over the next two years, with general availability – assuming all goes well – by the end of 2027. ®