An Investigation of the Degradation of a Laser Beam by High Intensity Turbulence.

Abstract

The intensity reduction of the far field central spot formed by a collimated laser beam traversing intense turbulence was correlated with the statistical behavior of the refractive index perturbations causing the intensity reduction. An analytical method to predict the intensity degradation using readily measurable statistical turbulence parameters was developed. An experiment to measure the actual far field central spot intensity reduction and the temperature and velocity perturbations causing that reduction was conducted. A one by ten centimeter nozzle with laminar, uniform velocity/temperature profile exhaust air created the turbulence. A He-Ne laser with 50.0, 26.8 and 11.0 mm diameter beams and a He-Cd laser with 50.0, 26.0 and 12.3 mm diameter beams were used. The actual far field central spot intensities were measured. The average difference between the experimentally and analytically determined far field degraded intensities was less than two percent.

Document Details

Document Type
Technical Report
Publication Date
May 26, 1976
Accession Number
ADA025658

Entities

People

  • George F. Cudahy

Organizations

  • Air Force Institute of Technology

Tags

DTIC Thesaurus Topics

  • Degradation
  • Diameters
  • Far Field
  • Intensity
  • Laser Beams
  • Lasers
  • Perturbations
  • Physical Properties
  • Refractive Index
  • Turbulence

Fields of Study

  • Physics

Readers

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

Technology Areas

  • Directed Energy