Analysis of Technology for Solid State Coherent Lidar

Over the past few years, considerable advances have been made in the areas of the diode-pumped, eye-safe, solid state lasers, wide bandwidth, semiconductor detectors operating in the near-infrared region. These advances have created new possibilities for the development of low-cost, reliable, and compact coherent lidar systems for measurements of atmospheric winds and aerosol backscattering from a space-based platform. The work performed by the UAH personnel concentrated on design and analyses of solid state pulsed coherent lidar systems capable of measuring atmospheric winds from space, and design and perform laboratory experiments and measurements in support of solid state laser radar remote sensing systems which are to be designed, deployed, and used by NASA to measure atmospheric processes and constituents. A lidar testbed system was designed and analyzed by considering the major space operational and environmental requirements, and its associated physical constraints. The lidar optical system includes a wedge scanner and the compact telescope designed by the UAH personnel. The other major optical components included in the design and analyses were: polarizing beam splitter, routing mirrors, wave plates, signal beam derotator, and lag angle compensator. The testbed lidar optical train was designed and analyzed, and different design options for mounting and packaging the lidar subsystems and components and support structure were investigated. All the optical components are to be mounted in a stress-free and stable manner to allow easy integration and alignment, and long term stability. This lidar system is also intended to be used for evaluating the performance of various lidar subsystems and components that are to be integrated into a flight unit and for demonstrating the integrity of the signal processing algorithms by performing actual atmospheric measurements from a ground station.