AAPT Abstract Archive

Abstract Information

  Session: Upper Division Undergraduate
  Paper Type: Contributed
  Title: Faraday Isolators and the Second Law of Thermodynamics
  Meeting: 2016 Summer Meeting: Sacremento, California
  Location: N/A
  Time: 1:40PM
  Author: Carl E. Mungan, U.S. Naval Academy
410-293-6680, mungan@usna.edu
  Co-Author(s): None
  Abstract: Consider a Faraday isolator: two optical linear polarizers whose transmission axes are oriented 45 degrees relative to each other, between which is located a magnetic rotator that turns the plane of polarization of a beam of light by 45 degrees in the same direction regardless of the direction of propagation of the light. That constitutes a one-way light valve, used to protect lasers from harmful back-reflections. Now place a sample inside a cavity whose walls are made of this stuff. Light gets out but not back in, right? If so, the sample would radiate away all its energy and cool down to absolute zero! How do we save the second law from this catastrophe?
  Footnotes: None
  Presentation: AAPT_Mungan.pdf

2003 © American Association of Physics Teachers
Have questions about this site? Email the webmaster.
AAPT Home AAPT Abstract Archive Past Meeting Info