The Institute of Applied Physics (IAP) at Friedrich-Schiller-Universität Jena (FSU) is well-known for outstanding R&D in various fields of optics including micro- and nano optics, ultrafast optics, laser optics, and optical computing and system design. The institute belongs to the Faculty of Physics and Astronomy and contributes to the Abbe Centrum of Photonics. The institute has close collaboration with industry in Germany and abroad. The Applied Optical Computing group, which is headed by Prof. Frank Wyrowski, deals with modeling of optical systems with field tracing which combines geometrical and physical optics modeling techniques. Currently the emphasis in R&D is on modeling lithographic systems, laser resonators, ultrashort pulses, scattering, and diffractive optics.