Design of a Triangular Active Ring Laser 13 m on a Side

The design and testing of a proof-of-principle triangular active ring laser interferometer ~13 m on a side is discussed. Issues such as lock in, multimode interference, mode hopping, and neon isotope mixtures are examined as they relate to large He-Ne ring lasers. Responses of the ring laser to Earth's rotation and perturbations that change its tilt or area are presented. Some potential applications are suggested for large interferometers.