Cambridge Heavy Industries, a Massachusetts startup developing a tabletop laser fusion device, has raised $6.2 million in seed funding as it works toward producing fusion fuel and eventually generating electricity. The company is pursuing a compact approach to nuclear fusion that could allow faster experimentation than larger reactor systems.
Azolla Ventures led the funding round, with Overlay, Neta Foundation, P3A, MassCEC, and the Rothrock family participating. Operating out of a small laboratory near MIT, Cambridge Heavy Industries has developed its technology largely out of public view.
Co-founder and CEO Yun Kai said the small, modular design lets researchers run 50 to 80 laser experiments daily. The results will feed AI-based simulations intended to improve the system’s performance and guide further design changes.
How Cambridge Heavy’s Tabletop Fusion System Works
The company uses inertial confinement fusion, a technique that compresses fuel with powerful laser pulses to create the conditions needed for nuclear fusion. Its design relies on two primary lasers rather than the much larger laser arrangements used in some other experimental systems.
One laser is divided into multiple beams arranged in concentric rings around a flat, circular fuel target. The outer ring strikes first, creating an inward-moving compression wave, while successive rings deliver carefully timed pulses that increase the pressure as the wave moves toward the centre.
As the compression wave converges, the second laser delivers energy to the target’s centre, generating heat and a magnetic field. The process is designed to create the pressure and temperature required for fusion while using comparatively modest laser power.
The technology originated in research conducted in the laboratory of MIT chemist Keith Nelson. Researchers studying how materials behave under extreme pressure found that their laser-driven experiments were approaching fusion-relevant conditions.
Tritium Production Is the First Commercial Goal
Rather than immediately building an electricity-generating reactor, Cambridge Heavy plans to use smaller devices to produce tritium, a rare hydrogen isotope many proposed fusion power plants require. The material is difficult to obtain and commands a high price; the American Chemical Society values tritium at about $30,000 per gram.
Limited supplies could become a serious obstacle as more fusion projects move toward operation. A study published in Fusion Engineering and Design projected a tritium shortage of about 28 kilograms by 2054 without additional supply sources.
Fusion developers are working on systems that would allow their reactors to produce much of the tritium they consume. However, those capabilities remain under development, and Kai estimates it could take as long as a decade to establish them. Cambridge Heavy hopes to serve that supply need while continuing to develop its fusion technology.
A Larger Fusion Power Plant Remains the Long-Term Plan
Cambridge Heavy aims to develop a larger experimental power plant within approximately 10 years. Kai estimates that the facility would occupy an area comparable to two basketball courts, substantially larger than the current benchtop system but smaller than many conventional fusion research facilities.
The planned facility would test whether the company’s laser-based approach can be scaled to produce enough energy for practical electricity generation. For now, it remains focused on refining the compact system and developing tritium production as a potential commercial business.
