In the Fraunhofer Cluster of Excellence Advanced Photon Sources CAPS, 21 Fraunhofer institutes combine their expertise in the development of laser systems that use ultrashort pulses (UKP) to achieve highest with ultrashort pulses. The Fraunhofer Institutes for Laser Technology ILT in Aachen and for Applied Optics and Precision Engineering IOF in Jena contribute their expertise in the development of high-power UKP lasers, which is combined in the cluster with the expertise of the other Fraunhofer Institutes in the areas of systems technology and the applications based on it.