Complete Interferometer System

Product Code: OS-9258B


No study of interferometry should overlook the historical importance of the Michelson interferometer. Yet in the laboratory, the Fabry-Perot and Twyman-Green interferometers can be more important tools: the first for high-resolution spectroscopy; the second for testing and producing optical components with aberrations that can be measured in fractions of a wavelength.

The PASCO Interferometer is a high-precision, movable-mirror interferometer that can be used to perform Michelson, Fabry-Perot, and Twyman-Green interferometry. The mirrors are attached with thumbscrews, so it’s easy to set up and change configurations.

The PASCO Interferometer can be ordered in a variety of systems. The Precision Interferometer can be operated in either the Michelson or Fabry-Perot modes. The Complete Interferometer Systems also contain components for the Twyman-Green mode and a vacuum pump for the refractive index of air experiment. The Systems Component List shows the contents of each system.


  • Stable: The massive (5 kg) base is machined from a single block of aluminum ensuring extremely stable optics.
  • Smooth Mirror Movement: With the taut-band suspension system, there’s no starting or stopping friction and virtually no backlash (less than 0.5 micron).
  • Precise Measurements: Mirror control is extremely fine: one micron per division of the micrometer head. The mirrors and beam-splitter are flat to 1/4 wavelength to ensure uniform interference patterns.
  • Larger Optics: The 3.2 cm (1-1/4″) diameter optics in the PASCO Interferometer produce larger and sharper interference patterns for better experimental results.
  • Complete: The Basic Interferometer includes everything necessary to perform basic Michelson and Fabry-Perot interferometry.


  • Perform basic Michelson and Fabry-Perot interferometry
  • Demonstrate that cross-polarized beams will not interfere
  • Measure lens irregularities in Twyman-Green Mode
  • Measure the indices of refraction for air and glass
  • Measure the indices of refraction for user-supplied materials

Typical Experiments

  • Introduction to Interferometry
  • The Index of Refraction of Air
  • The Index of Refraction of Glass

What’s Included

Parts Available Separately

Double Convex Lens (18 mm) OS-9132

Support Documents