Dual-Wavelength Laser Heterodyne Interferometer for Absolute Displacement Measurement

In order to meet absolute metrology of the displacement in several axes simultaneously, the induced errors due to the fluctuation of atmospheric parameters and Doppler Effect should be investigated. This paper describes method to develop the capability of an optical heterodyne interferometer designed to measure linear and angular displacement with high measurement resolution (1.24nm). Measurements of phase dispersion and Doppler frequency shift over different axes using a stabilized dual-wavelength laser heterodyne interferometer (ZMI-1000A) are reported. However, the principle of this work is based on a study to detect and characterize the induced parameters due to the displacement along different-axis using dual-wavelength laser heterodyne interferometer.