Optical Magnetometry for Detecting Underwater Objects

Abstract

.A method for remote optical measurements of magnetic field variations above the surface of seawater is analyzed. This magnetometry mechanism is based on the fact that polarized laser light, in the presence of the Earths magnetic field, will exhibit a polarization rotation when reflected off the surface of the water and off an underwater object. The two mechanisms responsible for the polarization rotation are the Surface Magneto-Optical Kerr Effect (SMOKE) and the Faraday effect. In both mechanisms, the degree of polarization rotation is proportional to Earths local magnetic field. Variations in the Earths magnetic field due to an underwater object will result in variations in the polarization rotation of the laser light reflected off the waters surface (SMOKE) and off the underwater object itself (Faraday effect). An analytical expression is obtained for the polarization-rotated field when the incident plane wave is at arbitrary angle and polarization with respect to the waters surface

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Document Details

Document Type
Technical Report
Publication Date
Oct 21, 2015
Accession Number
AD1000477

Entities

People

  • Phillip A. Sprangle
  • Zachary Epstein

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Advanced Electronics
  • Sensors

DTIC Thesaurus Topics

  • Coordinate Systems
  • Detection
  • Detectors
  • Dielectric Properties
  • Electric Fields
  • Electrons
  • Equations
  • Faraday Effect
  • Frequency
  • Kerr Effects
  • Laboratory Magnetometers
  • Magnetic Anomaly Detection
  • Magnetic Fields
  • Military Research
  • Refractive Index
  • Underwater Objects
  • Wave Equations

Fields of Study

  • Physics

Readers

  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Quantum Dot Semiconductor Device Photonics and Graphene Optoelectronic Materials and THz Physics.
  • Space/Atmospheric Physics.

Technology Areas

  • Directed Energy