Toward Adaptive Optic Mitigation of Aero-Optic Effects

Abstract

This report describes aero-optic research at the University of Notre Dame. When a laser beam propagates through a variable-index-of-refraction, turbulent fluid, its wavefront becomes aberrated, reducing associated optical-system performance. For flight Mach numbers as low as 0.3 Mach, turbulence in the flow past the aircraft become important in aberrating wavefronts (aero-optics). This report briefly reviews the mechanisms responsible for these aberrations in free-shear-layer flows. The report begins with describing an historic demonstration performed under this effort that combined the use of flow control and feed-forward adaptive optics to correct the aberrations imposed on an otherwise collimated laser beam projected through a heated jet and a Mach 0.8 free shear layer, respectively; this historic demonstration included a man in the loop. The report then describes the development of an automated control system that removes the man in the loop. Also described is some additional work performed under this grant that examined a spatial-filter approach to analyzing the effect of apertures on several aspects of laser-beam control.

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Document Details

Document Type
Technical Report
Publication Date
Feb 27, 2009
Accession Number
ADA501712

Entities

People

  • Eric J. Jumper

Organizations

  • University of Notre Dame

Tags

Communities of Interest

  • Energy and Power Technologies
  • Space

DTIC Thesaurus Topics

  • Adaptive Optics
  • Boundary Layer
  • Closed Loop Systems
  • Computational Fluid Dynamics
  • Control Systems
  • Diffraction
  • Distortion
  • Fluid Dynamics
  • Hypervelocity Flow
  • Laser Beams
  • Mach Number
  • Optics
  • Refraction
  • Refractive Index
  • Turbulence
  • Turbulent Mixing
  • Waveform Generators

Fields of Study

  • Physics

Readers

  • Fluid Mechanics and Fluid Dynamics.
  • Optical Physics and Photonics.
  • Robotics and Automation.

Technology Areas

  • Directed Energy