Breakthrough: UV light on photonic chips 100 times more powerful

Scientists at the University of Twente (UT) and Harvard University have taken an important step toward more powerful and practically applicable photonic chips. They developed a new method to generate ultraviolet (UV) light directly on a chip. For the first time, this technique produces UV light at milliwatt power levels. This is sufficient for real-world applications, such as quantum technology, optical atomic clocks, and ultra-precise measurement systems. The UT spin-off Sabratha is bringing this chip technology to market for telecom and wireless applications.

Integrated light sources form the foundation of many modern technologies. For example, data is transmitted through optical fibers using infrared light. However, more advanced applications, such as molecular-level sensing and quantum computers, require shorter wavelengths, including UV light. Until now, it has been difficult to produce high-quality UV light on chips. As researcher and CEO of Sabratha, Kees Franken explains, every application requires a specific “color” of light, and existing chip technologies have fallen short, especially at shorter wavelengths.

From red to UV light

The breakthrough is based on a clever conversion process. The researchers start with red light, which has been relatively easy to generate on a chip for several years. They then convert it into UV light through a process in which two red photons combine into a single, higher-energy UV photon. Although this principle was already known, it previously produced only minimal light intensity on chips. With this new approach, the output is increased by roughly a factor of 100, reaching a practically useful level.

A unique material and extreme precision

The key to this success lies in a material called thin-film lithium niobate (TFLN), which is known for its exceptional optical properties. Simply put, TFLN can be compared to a super-fast, well-built, and smoothly operating highway, free of potholes or traffic. Using this material, the researchers created a nanoscale waveguide, a structure that precisely and efficiently guides and confines light on the chip.

What makes their design unique is the extreme level of control. The waveguide, nearly two centimeters long, was mapped with very high precision, down to just a few dozen atomic diameters. Along this structure, thousands of tiny electrodes were placed, each carefully tailored to the exact shape of the waveguide at that specific point.

By alternately switching voltage on and off across the electrodes, the researchers create a pattern in the material’s crystal structure, with up to a thousand variations per millimeter. This pattern enables efficient conversion from red to UV light. Unlike earlier designs, where electrodes were positioned at a distance, they are placed directly on the waveguide here, significantly improving efficiency.

UV Chips as a key to scaling quantum technology

One of the biggest challenges in fields such as quantum computing and optical atomic clocks is scalability: the transition from complex laboratory setups to robust, widely deployable systems. Currently, these technologies rely heavily on large, specialized laser systems, whose design, stabilization, and integration can take years. As a result, scaling up to practical applications or larger systems can easily take a decade or more.

Integrating UV light directly onto a chip offers a promising solution. By miniaturizing these light sources, complex optical setups can be replaced with compact, mass-producible chips. This makes systems not only simpler and more reliable, but also much easier to scale.

As such, UV light on chips represents a crucial development for applications that depend on extremely precise light control, including quantum computing, spectroscopy, and advanced timing systems. Moreover, this technology opens the door to space-based applications: because photonic chips are small, generate little heat, and require minimal power, they are particularly well suited for integration into satellites and other space platforms.