The Multilayer laboratory provides advice, support, research and development in multilayer based optical elements.

It also characterises multilayer optics for ESRF beamlines and external partners and customers.

The ESRF Multilayer Laboratory is in charge of the development and the production of multilayer coatings for X-ray optical devices. It provides advice to ESRF beamlines and works in close collaboration with the Mirror and Metrology Laboratory, the Crystal Laboratory, and the beamline BM05. In addition, the Multilayer Laboratory responds to fabrication requests from external partners and customers. The core of the laboratory is a sputter deposition facility where substrates up to 100 cm long and 15 cm wide can be coated with multilayers of desired repetition period and thickness gradient. All multilayers are characterized using a laboratory X-ray reflectometer. More demanding performance tests can be carried out on the beamline BM05. Computational algorithms are used to simulate the optical properties of multilayers and to retrieve their structure.

Multilayers

A multilayer is a stack of (usually two) alternating thin layers deposited on each other. The resulting structure has a repetition period of a few nanometers. Due to different optical indices of the two layers, the whole stack acts like a one-dimensional artificial Bragg reflector when exposed to an X-ray beam. Multilayer based optics cover hard X-rays with photon energies between 5 keV and 100 keV. Their peak reflectance can reach 90% and their energy bandwidth can be tuned between 0.25% and 20%. The most prominent applications are focusing devices and high-flux monochromators.