Harnessing the power of light: A European history of photonics

A woman visits the exhibition 'Mirrors: In and Out of Reality' in Barcelona, Spain, 12 April 2019. Math, physics and photonics melt in this exhibition presented by Cosmocaixa in which visitors can enter a big kaleidoscope to walk through and experience with the effects and particularities of mirrors. [EPA-EFE/Quique Garcia]

This article is part of our special report How the light gets in: Europe’s Photonics Landscape.

Europe has a long and rich history of harnessing the power of light to extend the technical and practical capacities of the human species. The modern-day utilisation of light for such means takes its form in the technology of photonics, and today, Europe’s clout in the arena is formidable.

Currently, the continent ranks second only to China in the global photonics market, and projections estimate that the sector could attain a compound annual growth rate of 8.6% leading up to 2022.

While today photonics technologies are used in high-tech applications such as quantum computing applications, Internet of Things devices, wearable devices, self-driving cars, and healthcare technologies, the origin of Europe’s relationship with light technologies stretches back millennia.

In order to unlock the technological possibilities of tomorrow, our ancestors first had to wrestle with the mystifying theoretical foundation of the material property known as light, and it befell one of Europe’s most dominant civilisations, the ancient Greeks, to first pursue this tract.

One of the earliest influential documentations on materials theories of light appeared in mathematician Euclid’s treatise on vision, whose earliest surviving manuscript dates from the 10th century.

Euclid’s postulated over the geometrical properties of light  – leading him to conceptualise the law of reflection. Euclid, along with Greek mathematician Ptolemy, subscribed to what is known as emission theory  – the notion that the visible perception of things occurred as a result of the eyes themselves emitting rays of light.

Inspired by Euclid and Ptolemy’s work, the Arab mathematician Ibn al-Haytham hypothesised that the objects themselves radiate light.

The next most relevant development on photonics back in Europe came by way of Issac Newton’s work in the 17th century. Based on his renowned prism experiment, he concluded that “light is a mixture of various colours having different refractivity,” which eventually formed the basis for his Light Particle Theory as outlined in the 1704 title Opticks.

One of the main opponents to Newton’s theory was the Dutch mathematician Christiaan Huygens, who, being inspired by Rene Descartes’ 1637 treatise, Dioptrics,  believed that light took the form of waves.

Planck and Einstein make the leap

But it finally fell upon Max Planck and then Albert Einstein to make the greatest scientific leaps in photonics research, and reveal the true nature of light.

Planck’s contribution to the world of quantum physics was a momentous leap in the pursuance of photonics technologies. In 1900 Planck managed to find an association between the amount of energy that a photon is able to carry and the frequency of the wave by which it travels  – giving rise to the now famous ‘Planck’s Constant’ theory.

In 1905, Einstein published a paper refuting the commonly accepted proposition that a light-beam is a wave travelling through space, contending instead that it is an amalgam of discrete wave ‘packets,’ later dubbed ‘photons,’ that each contain a quantity of energy. Einstein discovered that as part of the photoelectric effect, the phenomena of photons striking elections, light was never made up of merely waves nor particles, but in fact both.

Einstein has settled the age-old theory on the material properties of light, and in so doing, was awarded the 1921 Nobel Prize for Physics.

Einstein is the father of modern photonics technologies, and without his findings, many of the applications used across Europe’s optical industries would probably never have come into being.

In terms of European innovation, Einstein’s work became fundamental in many later technological developments, including Hungarian-British scientist Dennis Gabor’s 1948 invention of holograms, and more modern applications, such as the University of Regensburg in Germany’s research into how laser-light pulses can be used in quantum computing.

Revolutionary potential

More broadly, from computer screens to lasers in healthcare devices and solar panels, from cameras in smartphones to optical fibre technologies, the revolutionary potential of photonics has been recognised by the European Commission as a Key Enabling Technology of the 21st century.

In this vein, a 2018 report by the European Investment Bank recognised the potential of photonics technologies to enrich and extend the capabilities of other next-generation applications, which, without Europe’s history in scientific research, would never have been possible.

“Deep tech applications such as artificial intelligence, big data, additive manufacturing, robotics, the Internet of Things (IoT), and autonomous driving will require faster, more reliable, more energy efficient and more powerful photonics and semiconductor components,” the report states. ”

“The success of Europe in this next wave of innovation will ultimately depend on photonics and semiconductor components.”

With Europe’s valiant scientific excursions into the theory of light and photoelectric research being well-established, there are also those who have touted photonics as an area in which the wider political goals of the European Union can be pursued.

While the Von der Leyen Commission has been quick to employ the term ‘sovereignty’ across the digital and data fields, there are those who believe that amid the current global economic climate, Europe must place an emphasis on an industry that bears the development of so many other technologies.

A recent paper entitled Exploration of Photonics Markets, published by the industry lobby Photonics21, found that China’s annual spending in photonics will hit €1 billion in 2020.

There are concerns that Europe’s well-established research in light technologies could fall by the wayside while larger global players commit to substantial investments.

A December 2018 letter penned by leading scientists in the field brought these concerns to the fore, highlighting the importance of photonics technologies playing a central role in the Digital and Industry section of the next Horizon budget 2021-2027.

Carlos Lee, director-general of the European Photonics Industry (EPIC), recently told EURACTIV that photonics technologies should be heralded as a “European success story.”

And, looking at the figures, it’s hard to disagree. Estimates published by EPIC show that the photonics sector, built up predominantly of SMEs, features around 5,000 companies that have created more than 300,000 skilled jobs, with an annual turnover of €60 billion.

These fast-growing figures are a testament to Europe’s intellectual, scientific and philosophical history in theorising the properties of light, and how such a source can be harnessed to transform our technological landscape.

Only time will tell whether the continent will be able to distinguish itself further in this domain by ensuring that photonics remains at the forefront of the technological developments of tomorrow.

[Edited by Zoran Radosavljevic]

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