Macalester College is introducing interferometry into the undergraduate physics program through an advanced laboratory course on laser spectroscopy and faculty/student collaborative research. This is accomplished through the use of three different interferometers: a Michelson interferometer, a high finesse spherical interferometer, and a large aperture plane-parallel Fabry-Perot interferometer. All of these instruments are used to illustrate the concepts of free spectral range, finesse, and instrument profile introduced in the Laser Spectroscopy course. The Michelson interferometer is used to investigate optical Fourier transform spectroscopy as an example of the power and limitations of the transform techniques that have become so widespread in modern science. The spherical interferometer is used to study the cavity modes of different laser systems, such as He-Ne, dye, and diode lasers. The plane-parallel interferometer is used as a high resolution spectrometer to study laser, atomic vapor, and solid state light sources. The latter two instruments illustrate the hierarchy of optical bandwidths, from the inhomogeneous Doppler profile of a gas to the gain limited bandwidth of a single mode laser. Two general purpose computers control and analyze the data from the new instruments. A graphic programming language allows students to program these computers quickly and efficiently. The instruments support faculty/student research in solid state spectroscopy, fiber optics, and astronomy when the Laser Spectroscopy course is not in session. The College is matching the award with an equal amount of funds.4
