Alain Brillet passed away. He was one of the fathers of gravitational wave research

It is with great sorrow that we announce the passing of Alain Brillet, French physicist, who has been one of the founding fathers of gravitational interferometry and Virgo, along with Adalberto Giazotto, who left us in 2017.

The pioneering work of Brillet and Giazotto in the late 1980s, driven by the idea of using large laser interferometers to detect gravitational waves, contributed to lay the foundations for the discovery of this extraordinarily faint cosmic signal. At a time when much of the scientific community viewed their frontier research with scepticism, Brillet and Giazotto’s visionary tenacity led to the founding of Virgo in the 1990s near Pisa, in Italy, thanks to the support of the French National Centre for Scientific Research, CNRS and the Italian National Institute of Nuclear Physics, INFN.
Looking back several decades later, it is clear just how crucial Allain Brillet’s contribution was in laying the foundations for what we now call gravitational astronomy, and for the exceptional scientific results achieved in recent years by the gravitational wave antennas LIGO and Virgo.

“Alain Brillet was a visionary scientist, a talented physicist and one of the founding fathers of Virgo. His intuition, determination, and leadership were essential in bringing our detector and collaboration to life. The entire Virgo Collaboration is deeply grateful for his extraordinary legacy, which continues to inspire our work every day. Our thoughts are with his family.” declared  Gianluca Gemme, Virgo spokesperson and INFN researcher and Nelson Christensen, Artemis director and CNRS researcher.

“The European Gravitational Observatory (EGO) and the Virgo Collaboration would not exist as we know them today without the work of Alain Brillet. We express our deepest gratitude to him and our most heartfelt condolences to his family, friends and colleagues.“ said EGO Director Massimo Carpinelli

Born on March 30th 1947 at Saint-Germain-en-Laye (France), Alain Brillet received his engineering degree from ESPCI in 1970. He joined the CNRS the same year as a research engineer at the Laboratoire de l’Horloge Atomique in Orsay, where he defended his doctoral thesis in 1976, and was appointed senior researcher in 1982, after a post-doctorate in Boulder (Colorado, USA) in the team of John Hall (2005 Nobel Prize in Physics).

In the beginning of the 80s he started developing the project of an interferometer for the detection of gravitational waves and in 1985 at a conference in Rome he met another scientist who had the same dream: Adalberto Giazotto. Their areas of expertise were complementary to tackle some of the biggest issues they would face in the design of what would become Virgo: Brillet was an expert in lasers and started developing one that would be suitable for the detector, while Giazotto and his team started working on the superattenuator, to isolate the mirrors from seismic vibrations.

In 1989 they made a joint proposal to INFN and CNRS to create an Italian-French collaboration and build the Virgo detector. The proposal was approved in 1994 and led to the creation of the European Gravitational Observatory as a consortium with the scope of building and operating Virgo, which was inaugurated in 2003.

In 1999, he and his team moved to the Observatoire de la Côte d’Azur to be closer to Virgo. He created the Artemis laboratory (CNRS/Université de la Côte d’Azur/Observatoire de la Côte d’Azur) to continue to develop cutting-edge technologies for the lasers of the future detectors.  From 2008, he devoted his time to the design of the optics and laser system of Advanced Virgo, the upgrade to the existing detector. 

He was a senior researcher emeritus at the Artemis laboratory. In 2017, he was awarded the CNRS Gold medal along with Thibault Damour. He was also awarded the Ampère Prize of the French Academy of Sciences in 2016, the Special Breakthrough Prize in Fundamental Physics and in 2025 the Amaldi Medal by the Italian Society for General Relativity and Gravitational Physics (SIGRAV).