A subnanometre heterodyne interferometric system with improved phase sensitivity using a three-longitudinal-mode He-Ne laser

摘要

We present a high-resolution heterodyne interferometric system using a high output-power, three-longitudinal-mode He-Ne laser. In this system, an interferometric wavelength ofλ/2 is synthesized with the super-heterodyne detection of the three modes, resulting in twice the sensitivity for the target displacement in comparison with the conventional two-frequency interferometer. In the experiment, the achievement of subnanometre resolution has been confirmed.