Scintillation Control for Adaptive Optical Sensors

Abstract

Michigan Technological University (MTU) has been investigating strategies for overcoming the effects of scintillation on adaptive optical imaging and laser beam projection systems which must operate in the presence of extended path turbulence. The approach origin ally proposed under this contract involved using two deformable mirrors to fully conjugate the received or transmitted beam. Our investigations into this concept have shown that implementation details associated with the use of real adaptive optical hardware will likely limit the effectiveness of the two deformable mirror technique. As a consequence, an alternative approach using one deformable mirror was developed, and its performance was investigated. This technique exploits the fact that, under strong scintillation conditions, information about the phase of the beacon field is incorporated in the intensity of the beacon field. Hence, deformable mirror commands which are consistent with all of the intensity measurements available to an adaptive optical system are processed using a new nonlinear optimization based algorithm. Our studies of the performance of this technique have shown that under conditions of saturated scintillation this new approach significantly outperforms the standard centroid based processing of the Hartmann sensor measurements. An experiment conducted at MTU has demonstrated the ability to predict a laser intensity pattern in a distant target plane using Hartmann sensor measurements of the field reflected from a deformable mirror. One accepted journal article, and one submitted journal article have resulted from this work, along with three conference papers. In addition, this work forms the basis of a program which is now being conducted with the Airborne Laser Technology Division.

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Document Details

Document Type
Technical Report
Publication Date
Sep 21, 1999
Accession Number
ADA372491

Entities

People

  • Michael C. Roggemann

Organizations

  • Michigan Technological University

Tags

Communities of Interest

  • Air Platforms
  • Sensors

DTIC Thesaurus Topics

  • Algorithms
  • Amplifiers
  • Cameras
  • Deformable Mirrors
  • Detectors
  • Diffraction
  • Digital Cameras
  • Distortion
  • Dynamic Range
  • Far Field
  • Intensity
  • Laser Beams
  • Lasers
  • Light Sources
  • Measurement
  • Optical Detectors
  • Two Dimensional

Fields of Study

  • Physics

Readers

  • Image Processing and Computer Vision.
  • Space/Atmospheric Physics.
  • Technical Research and Report Writing.

Technology Areas

  • Directed Energy