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Few people know what photonics actually is, even though it's a fundamental part of our everyday lives. Photonics is the study of light and electromagnetic radiation – how it's generated, transmitted and controlled. At the heart of this field are photons, the particles of light itself.

Paul Verrinder, Assistant Professor of Electrical Engineering at Aalto University, shares five things everyone should know about photonics right now.

1. Photonics is already part of our everyday life

Fibre-optic cables, which carry data using lasers, increasingly power the internet's data transfer network. In addition to telecommunications and data centres, photonics is used in satellites, medical imaging, and in self-driving cars.

2. Light moves information efficiently

Does information travel at the speed of light? Partly, but what makes light such a powerful way to send data is its frequency and its low loss in optical fibre. Because light has a higher frequency, it has greater bandwidth, meaning it can carry more information. Its low loss also enables transmission over longer distances than electrical signals.

'Think of bandwidth like a motorway. Instead of one fast lane, many lanes can deliver far more information across the same distance. Light is also suited to travel long distances, even between continents. For example, electrical signals in copper wires lose energy so quickly they need amplification every few kilometers, whereas light can travel hundreds of kilometers in fiber without needing a boost,' Verrinder explains.

Verrinder notes that electronics are good at scaling up and handling binary computation, something photonics struggles to do efficiently. That's why both are needed.

3. Combining materials is what unlocks future solutions

Public discussion often focuses on individual wonder materials, but Verrinder argues it's really the interplay between materials that matters most. Without the right material, he says, a laser is like a car without an engine.

'Silicon is still the backbone of electronics, but it isn't very good at producing light on its own. That's why other semiconductor materials are used as light sources and detectors. Some are far more efficient at converting electricity into light and back again,' Verrinder explains.

Scalability and cost matter in choosing semiconductor materials. According to Verrinder, gallium arsenide and indium phosphide generate light efficiently and are used in most lasers, but they cost more than silicon, which is used for waveguides and electronics. This is why hybrid designs combine the two materials, pairing efficient light generation with affordable, scalable manufacturing.

4. Photonics makes data centres more energy-efficient

AI's growing computing demands continue, but meeting them will require progress in core materials and scaling up the technology as a whole. Verrinder says that making data centres more energy-efficient and sustainable will require new materials, better heat management, and improved methods integrating everything together.

He points to Nvidia, which is beginning to deploy what's known as co-packaged optics. It means physically packaging electronic and photonic chips in a single unit.

'With co-packaged optics, the signal has less distance to travel, which makes data transfer more efficient. Nvidia estimates this could cut energy consumption by a factor of five compared with current approaches,' says Verrinder.

5. Technology moves on, but photonics expertise doesn't go out of date

According to Verrinder, building the physical hardware is the biggest challenge and the main bottleneck for progress. Electronics has been scaling up for decades, but AI's computing demands are growing even faster.

Emerging core technologies, such as new wavelengths and better detectors, will shape what's possible in the future. Individual devices and solutions will come and go, but according to Verrinder, the underlying expertise in designing and building semiconductor components will keep its value.

'Working in photonics builds deep, hard-won expertise that machines simply can't replace,' Verrinder concludes.

Text: Mariia Kukkakorpi