Laser interferometry by induced modulation of cavity field

Abstract

The field backscattered from a remote surface into the laser cavity induces an efficient modulation, both in amplitude and frequency, of the cavity field. The modulating signals are the interferometric components (sin and cos) of object optical path length, which can be recovered by heterodyne detection through a separate reference-frequency mode. Using a dual polarization Zeeman stabilized He-Ne laser, a compact self-aligning interferometer is developed.