Interferometry

This demonstration shows the Michelson interferometer which produces interference fringes by splitting a beam of monochromatic light so that one beam strikes a fixed mirror and the other a movable mirror. When the reflected beams are brought back together, an interference pattern results from the differences in path lengths traveled.

A Michelson interferometer with a green laser but without a viewing screen. The JDSU laser unit is simply used to block the green laser from traveling farther into the room.

A Michelson interferometer with a red laser. Instead of a viewing screen attached to the interferometer base, this setup uses a clipboard at a greater distance to see a larger image of the interference patterns.

The interference patters of a red laser with a Michelson interferometer.

Setup:

This demo may take some time to set-up. While there aren't many steps to get the interferometer running, they can take many tries to get right. Carefully watch the above video and try to follow along with the kit. If there are any difficulties, see the Precision Interferometer Manual for troubleshooting advice.

Notes:

The PASCO precision interferometer can be used with a variety of interferometer types. The Michelson method is discussed in the video above, while the Fabry-Perot is briefly mentioned. The kit is compatible with Michelson, Fabry-Perot, and Twyman–Green setups.

Multiple experiments can be performed with this interferometer. Some examples are measuring the wavelength of the light source, the index of refraction of air, and the index of refraction of glass.

For more information on how to assemble the various interferometer setups and conduct the recommended experiments, please see the Precision Interferometer Manual.

Courses Used In:

Coming Soon

Discussion and Polling Questions:

Coming Soon

Equipment Needed for Michelson Interferometer:

  • PASCO Precision Interferometer base

  • Laser light source

  • Convex lens (18mm)

  • Component holder (x2)

  • Movable mirror

  • Adjustable mirror

  • Viewing screen

  • Beam splitter

  • Compensator

Optional Equipment and Accessories:

  • Rotational pointer

  • Convex lenses (18mm, 42 mm)

  • Component holder

  • Polarizer (x2)

  • Vacuum cell

  • Vacuum tubing

  • Diffuser

  • Glass plate

  • Hand-operated vacuum pump