The Einstein Telescope (ET) requires mirrors with sub-nanometer flatness to detect the faintest ripples in spacetime. As a key partner in the SPACE-ECHO consortium, cosine is leading the development of the specialised polishing processes required to meet these extreme standards.
To achieve the required sensitivity, the ET mirrors must be cooled to cryogenic temperatures and polished to an extraordinary sub-nanometer flatness. Crystalline silicon is the material of choice, but mastering the polishing process at this scale requires a special expertise.
Following Siltronic successfully delivery of the primary materials, these materials are currently being processed, where large silicon blocks are cut, cored, and sliced into numerous smaller samples. At cosine, we are using these samples to rigorously test different polishing pressures, duration, and chemical environments. This systematic approach allows us to define the exact processes needed to achieve the ±2 nanometer flatness required for the final ET mirrors. Our role leverages decades of experience in silicon processing for Silicon Pore Optics (SPO), bridging the gap between space-proven technology and the next generation of gravitational wave astronomy.
This development is a collaborative effort within the SPACE-ECHO consortium, involving Maastricht University, TNO, NOVA, SRON, VSL, and cosine. With the arrival of these specialised samples, we are now positioned to finalise the high-precision techniques that will allow the Einstein Telescope to listen to the furthest reaches of our universe.
About the Einstein Telescope
The Einstein Telescope (ET) is a proposed third-generation, underground ground-based gravitational-wave observatory designed to detect space-time ripples with 10 times the sensitivity of current detectors. By operating at cryogenic temperatures to reduce thermal noise, it aims to unravel mysteries of fundamental physics, astrophysics and cosmology.
About cosine
For over 25 years, cosine has delivered advanced measurement systems that make the invisible measurable and the complex actionable. As a trusted partner to ESA and global commercial innovators, we design and build high-performance optical, electronic, and mechanical systems that operate from deep space to extreme terrestrial environments. From our offices in the Netherlands, Germany, and Italy, our multidisciplinary teams transform scientific discovery into precision systems that provide real-world impact for our space and planet.
