TWO-DIMENSIONAL DISPLACEMENT MEASUREMENT USING WAVELENGTH-MODULATION HETERODYNE GRATING INTERFEROMETRY
Abstract
A wavelength-modulation heterodyne grating interferometry for two-dimensional displacement measurement is proposed. This technique has the advantages of heterodyne interferometry, grating-based interferometry, and Michelson interferometry. A heterodyne light beam is obtained from a tunable diode laser using the triangular wave modulating method. While the heterodyne light beam is normally incident into a transmission type grating, two detection parts for in-plane (IP) and out-of-plane (OP) displacement measurements will be obtained. The optical phase variations resulted from the moving grating in OP direction and IP direction are carried on the heterodyne interference signals. By means of measuring the phase variations of the interference signals from the moving grating, the grating movement in two dimensions can be acquired simultaneously without changing the optical configuration. The experimental results show that our proposed wavelength-modulation heterodyne grating interferometry is capable of sensing two-dimensional displacement with high measurement resolution. The measurement range and resolution can achieve millimeter and nanometer levels.
Event details
- Event
- TC14 LMPMI Symposium 2014
- Technical Committee
- TC14
- Place
- Tsukuba, JAPAN
- Time
- 3 September 2014 - 5 September 2014
- Website
- http://www.lmpmi2014.jp/