Christophe Collette wins ERC PoC funding for his GrAVITe project
The GrAVITe project (Gyroscope for Active Vibration Isolation of Telescopes), led by Professor Christophe Collette - director of the Precision Mechatronics Laboratory (School of Engineering) - has been awarded Proof of Concept funding from the European Research Council (ERC). Directly linked to the Einstein Telescope project, GrAVITe aims to develop and validate a large-scale optical gyroscope capable of improving the vibration isolation of high-precision instruments at the lowest frequencies.
Many state-of-the-art instruments are hypersensitive. Ultra-stable lasers, bolometers cooled to very low temperatures, machines used to etch microchips, and quantum computing devices all have their performance compromised by even the slightest vibration. Large gravitational-wave detectors, such as the future Einstein Telescope, are the most striking example of this. To detect the Universe’s minute tremors, they must be almost completely isolated from the ground’s constant vibrations. To achieve this, these instruments are mounted on platforms that continuously readjust themselves, much like a tightrope walker constantly correcting their balance. Sensors monitor ground movements and indicate how to compensate. But these sensors have a blind spot. They confuse genuine displacement with a simple tilt. As a result, whilst trying to stabilise the platform in one direction, it is destabilised in another.
The GrAVITe project aims to overcome this obstacle by replacing these sensors with an optical gyroscope. Instead of a swinging mass, it uses light to measure rotation, thanks to the Sagnac effect. “Two light beams travel along the same loop in opposite directions,” explains Christophe Colllette, an aerospace engineer at ULiège. “As long as everything is stationary, they return at the same time. But as soon as the device rotates, one of the two arrives with a slight delay, and it is this tiny discrepancy that reveals the rotation. As the measurement relies solely on light, and not on the weight of a mass, this sensor is not affected by tilts.”
Such a gyroscope is all the more accurate the larger it is. The idea is therefore to install it on the large structure of the SILENT platform - developed by Christophe Collette thanks to an ERC Consolidator grant - to measure its rotations directly. The device is also designed to ignore constant movements, such as the Earth’s rotation, in order to detect the much more subtle variations that really matter.
The GrAVITe project is a proof-of-concept, as the principle has already been demonstrated on a small scale by the French company MAÅGM, with which ULiège is collaborating. The challenge for GrAVITe is to prove that it works on a large scale. The demonstration will take place in two stages: first on a small prototype tested in a vacuum chamber, then on the full-scale SILENT platform, with independent sensors to assess the results. If successful, this would be the first time such an approach has been validated under real-world conditions.
Beyond gravitational waves, potential applications include seismology, geodesy, astronomy (such as satellite pointing), microchip manufacturing, quantum computing and navigation. Demand for ultra-high-precision gyroscopes is growing, but GrAVITe is aimed solely at niche applications, where measurement precision and long-term stability make all the difference. If the expected performance is achieved, GrAVITe could help extend the detection range of future gravitational wave detectors towards lower frequencies, and inspire the development of other highly precise rotation-measuring instruments.
About the ERC Proof of Concept (PoC) funding
This scheme is aimed at researchers who hold a current or recently completed ERC grant (Starting, Consolidator, Advanced or Synergy), and enables them to explore the innovative, commercial or societal potential of an idea arising from their ERC-funded basic research. It takes the form of a lump sum of €150,000, for a period of up to 18 months. It is used, in particular, to test and validate an idea, to clarify the intellectual property and knowledge transfer strategy, and to engage industrial partners. For GrAVITe, the idea stems directly from Professor Collette’s ERC Consolidator project SILENT (Seismic Isolation of Einstein Telescope). The commercialisation phase will be carried out with ULiège’s RISE (Research, Innovation, Support and Enterprises) department, in partnership with the company MAÅGM (Milli-AnGtrom Meter).
