Principle

With the aid of two mirrors in a Michelson arrangement, light is brought to interference. Due to the magnetostrictive effect, one of the mirrors is shifted by variation in the magnetic field applied to a sample and the change in the interference pattern is observed.

Benefits

• See that magnetic fields can change the geometry of objects
• Use a Michelson interferometer to measure quantitatively this most subtile effect
• Set up the instrument by yourself from separate components

Tasks

1. Construction of a Michelson interferometer using separate optical components.
2. Testing various ferromagnetic materials (iron and nickel) as well as a non-ferromagnetic material (copper), with regard to their magnetostrictive properties.

Learning objectives

• Interference
• Wavelength
• Diffraction index
• Speed of light
• Phase
• Virtual light source
• Ferromagnetic material
• Weiss molecular magnetic fields
• Spin-orbit coupling