2015 BFY II Abstract Detail Page

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Abstract Title: W43 - Direct and Lock-In Measurements of Faraday Rotation
Abstract: Faraday rotation is a justifiably famous phenomenon, since it provided the first-ever evidence of the relationship of magnetism to light.  The measurement of typically small Faraday-rotation angles by 'protractor and Polaroid' methods is good enough for demonstration purposes, but much better means of electronic detection are available.  This workshop leads participants into such methods tutorially by starting with Polaroids and extinction, then moving from dc electronic detection to ac detection and, finally, to the use of a lock-in amplifier to give vastly greater sensitivity than the usual demonstration methods provide.

Participants will:
• See a tabletop apparatus for demonstrating Faraday rotation by Polaroid-extinction methods
• Learn how a photodetector, plus a Polaroid not at extinction, allow electronic detection
• Change to ac magnetic fields, and see an ac signal of Faraday rotation
• Measure such ac signals with superb selectivity by lock-in methods
• Take away a tutorial on the lock-in detection of Faraday rotation, as an introduction to the use of lock-in amplifiers in general
Abstract Type: Workshop

Author/Organizer Information

Primary Contact: Barbara Wolff-Reichert
and Co-Presenter(s)
Jonathan Reichert, George Herold, David Van Baak, TeachSpin

Workshop Documents

Workshop Doc 1: Download the Workshop Doc 1
Workshop Doc 2: Download the Workshop Doc 2