The Open Polarimeter: A High-Resolution Instrument Made from Inexpensive Optomechanical Parts

The Open Polarimeter (“Opol”) is a phase-based, high-resolution laser polarimeter formed from a small number of inexpensive optomechanical parts. The complete instrument can be assembled from scratch in two days for less than US$250, using only a 3D-printer and a benchtop milling machine. However despite its low cost Opol achieves a high accuracy of a few millidegrees, comparable to far costlier commercial instruments. It is released here as open hardware, with technical diagrams, a full parts list, and source-code for its firmware included as Supporting Information. Beyond polarimetry, Opol’s easy-to-build and versatile optical mounting system is likely to prove useful for a wide variety of optical systems.