A Laser Interferometer for the Undergraduate Teaching Laboratory Demonstrating Picometer Sesitivity

We describe a laser interferometer experiment for the undergraduate teaching laboratory that achieves picometer sensitivity in a hands-on table-top instrument. In addition to providing an introduction to interferometer physics and optical hardware, the experiment also focuses on precision measurement techniques including servo control, signal modulation, phase-sensitive detection, and different types of signal averaging. After students assemble, align, and characterize the interferometer, they then use it to measure nanoscale motions of a simple harmonic oscillator system, as a substantive example of how laser interferometry can be used as an effective tool in experimental science.