HIGH RESOLUTION HETERODYNE INTERFEROMETRIC METHOD AND SYSTEM

摘要

A high resolution heterodyne interferometric method and system are provided. The invention uses two parallel beams (8, 9) with different frequencies and the two parallel beams are oriented in diagonal position in the incident plane of the beam splitter (1); the invention generates two measurement signal with opposite Doppler shift. The structure is also balance. The measurement is insensitive to the thermal variation, and the periodic nonlinearity is essentially eliminated by using two separated beams. Therefore, the resolution is two times higher than the traditional interferometer.