Suchergebnisse

The US Air Force has need of parabolic-shaped membrane mirrors for surveillance satellites. The current polymer membrane technology has been unable to overcome shape deformation problems caused by intrinsic stresses from the membrane casting and mounting processes. One proposed solution was to coat the membrane mirrors with a stressed coating to compensate for shape deformations. Thus, the research presented in this dissertation produced controlled-stress large-area pulsed laser deposition (PLD) grown thin films on polymer substrates and investigated optical time-of-flight (TOF) sensor systems and Raman spectroscopy for control for the PLD process with respect to thin film stress. Initially, the PLD-grown film stress was controlled using a constant combination of deposition parameters. Also, the velocity was extracted from the optical TOF data and indicated film stress. As such, the velocity was used to control the laser fluence in order to compensate for slight variations in deposition conditions, which improved the film stress run-to-run stability. Additionally, iterative and theoretical experiments produced large-area YSZ films with less than ten percent total thickness variations. Combining the controlled-stress and large-area aspects produced desirable compensations in shape to the polymer substrates. Finally, Raman spectroscopy was shown to be compatible with the PLD.