Marcel Benoist Swiss Science Prize 2025 awarded to the physicist Tobias Kippenberg

With an endowment of CHF 250,000, the Marcel Benoist Swiss Science Prize is regarded as the ‘Swiss Nobel Prize’. This year's laureate, Tobias J. Kippenberg, Full Professor of Physics and Head of the Laboratory of Photonic Integrated Circuits and Quantum Measurements at the Swiss Federal Institute of Technology Lausanne (EPFL), is being honoured for his outstanding scientific achievements in quantum optomechanics and the generation of optical frequency combs using optical microresonators. Professor Kippenberg and his team are conducting research at the interface between quantum and non-linear optics. His findings in quantum optomechanics have made it possible to observe quantum phenomena even in macroscopic (visible to the naked eye) mechanical systems, while his research into chip-based frequency combs laid the foundations for future technologies such as optical telecommunications.

Interaction of light

Professor Kippenberg has been researching quantum optomechanics for over 20 years. This field of research is dedicated to the interaction between light (photons) and mechanical objects at the quantum level, i.e. the level of atoms and subatomic particles. At this level, the laws of classical physics no longer apply. While quantum physics has enabled the quantum control of atoms, ions and molecules in recent decades, the quantum control of macroscopic mechanical oscillators has long posed a challenge. Such oscillators are ubiquitous in science and technology: they are used, for example, in time measurement, as filters in mobile phones, in atomic force microscopes or in gravitational wave detectors.

In 2005, Professor Kippenberg achieved a major breakthrough. He was the first researcher in the world to observe the effect of dynamic feedback amplification predicted by the Russian physicist Vladimir Braginsky back in 1969: radiation pressure from light can not only set objects in motion, but also amplify their movement. This process also produces sideband cooling, which is a laser cooling technique that is widely used today in experiments on quantum phenomena. Thus, quantum optomechanics made it possible for the first time to observe and research quantum phenomena on a macroscopic level.

Frequency combs for high-precision measurements

Optical frequency combs make it possible to count light cycles. Theodor W. Hänsch and John L. Hall were awarded the Nobel Prize in Physics in 2005 for this revolutionary discovery. Just two years later, Tobias Kippenberg and his team discovered a new method of using optical microresonators to generate frequency combs with exceptionally high repetition rates and optical bandwidths that fit on a single chip. This unexpected observation broke with the conventional dogma that optical combs can only be generated with pulsed laser sources. In doing so, they laid the foundation for a significant advancement in optical measurement technology and opened up a new field of research. The discovery of microresonator-based frequency combs has enabled many further advances: microcombs have the potential to significantly increase the data transmission rate. They have application potential in numerous other areas, including neuromorphic computing, ultra-fast distance measurements (LIDAR) and optical atomic clocks. Microcombs also offer a new experimental environment for research into complex physical systems and pattern formation in non-linear systems.

The researchers have also developed low-loss photonic integrated circuits based on silicon nitride. This means that chip-based optical frequency combs can be produced using conventional semiconductor manufacturing processes. In addition, this new low-loss waveguide technology has made it possible to combine a large number of optical systems on one chip, including an optical amplifier. The demand for such amplifiers, which deliver higher performance and are also more compact than previous generations of amplifiers, is increasing: high-performance computer systems, data centres and AI are dependent on being able to process ever larger volumes of data in the shortest possible time.

It is important to Kippenberg that his findings also find practical application: “Our research in the field of quantum optomechanics is basic research, but I am also particularly keen to lay the foundations for future technologies with our research into photonic integrated circuits.” By co-founding the company LIGENTEC, he has made low-loss photonic integrated circuits accessible to research and industry.

For Tobias Kippenberg, the Marcel Benoist Swiss Science Prize is “a great honour and recognition of the many individual contributions made by my research team over the past 20 years, and serves as motivation for me personally to continue to dedicate myself to my research.”

Joint award ceremony in the Parliament Building

The Swiss National Science Foundation (SNSF) was responsible for the scientific selection of the award winners on behalf of the Marcel Benoist Foundation and Fondation Latsis. The Swiss science prizes will be awarded at the Parliament Building in Bern on 6 November. The chairs of the respective foundations will present the prizes in the presence of Federal Councillor Guy Parmelin and National Council president Maja Riniker.