Quantum memory device startup, Photon Queue, has raised $4 million in a Seed funding round led by Playground Global.

It comes less than a week after the startup announced it had received $500,000 in funding from the New Mexico Economic Development Department and Roadrunner Venture Studios to support its expansion in the state.

In a statement, Photon Queue said its seed funding round will help to accelerate product development and allow it to increase manufacturing capabilities and customer deployments as the company continues to scale.

Founded in 2024 as a spinout from the University of Illinois Urbana-Champaign, Photon Queue develops quantum memories that store photons directly in free-space optical loops that use proprietary high-reflectivity mirror systems and optical switches.

Unlike other approaches which require cryogenics or vacuum systems, Photon Queue’s devices operate at room temperature with standard power requirements. Additionally, the devices are designed to be compatible with “virtually any wavelength,” making them compatible with photonic, trapped ion, neutral atom, and other quantum computing modalities.

The startup has already deployed its first commercial quantum memory device at Sandia National Laboratories and the University of Maryland.

“Useful quantum computing will require photons to move through networks with extraordinary precision, efficiency, and timing. That is the problem Photon Queue was founded to solve,” said Nathan Arnold, co-founder and CEO of Photon Queue. “In less than two years, we have taken technology from the lab to deployed commercial hardware with leading national lab and university customers. Our work with Sandia and the University of Maryland is a major validation point that quantum memory is becoming essential infrastructure for the next era of computing.”