Integrated free space optics is a widespread and important field in today's technology. This study outlines one application in atomic physics and quantum optics. Since optimized design requires the adequate mathematical treatment of light propagation in free space, this study deals with the various existing scalar methods of light propagation, including plane wave expansion, the Fresnel approximation, and ray-transfer matrices applied to geometrical optics and the ABCD-law for Gaussian beams. As do other scientific methods, these mathematical treatments have their own prerequisites. Consequently, the application scope of these methods is restricted. This thesis aims at relaxing some prerequisites for conventional methods and also at demonstrating new application aspects. Using a research project in atomic physics as an application example, this thesis is restricted to two main research fields: micro optics and deep lithography. The topic comprises a design tool for minimal optical systems, energy investigation in scalar fields, mask diffraction in thick absorbing resists with partially coherent illumination, a phase reconstruction method using the ambiguity function, lithographic fabrication of alignment structures for a fiber resonator, and fabrication of micro lenses using replication techniques
