Development of an Optical Far-Field Generator for Intersatellite Laser Interferometers

Kurzfassung

This thesis covers the development and characterization of an optical system that provides a laser beam with the key properties of a beam in the far-field. Such a far-field generator is necessary for testing environments of intersatellite interferometers. The resulting beam will be used in such a setup to simulate the received beam from a distant spacecraft and thus be part of the optical ground support equipment. The primary function of the far-field generator is to homogeneously illuminate a receiving aperture with a diameter of 8 mm with a flat wavefront. The thesis investigates different approaches for providing the required beam, describes the design of the optical system and evaluates its performance. In the developed system, an output beam with homogeneous intensity distribution is achieved by appropriately truncating a wide Gaussian beam. The resulting beam exits the system collimated with a quasi-flat wavefront. Analysis of the beam shows a flat-top intensity distribution and a root-mean-squared wavefront error of Lambda/46 at Lambda = 1064 nm. The intensity homogeneity in the resulting beam cannot be reliably assessed with the available equipment. It is concluded that the developed system provides a beam with the main characteristics of a beam segment in the far-field and that further experimental analysis of the intensity distribution is necessary.