title: Absolute positioning by multi-wavelength interferometry referenced to the frequency comb of a femtosecond laser.
abstract: A multi-wavelength interferometer utilizing the frequency comb of a femtosecond laser as the wavelength ruler is tested for its capability of ultra-precision positioning for machine axis control. The interferometer uses four different wavelengths phase-locked to the frequency comb and then determines the absolute position through a multi-channel scheme of detecting interference phases in parallel so as to enable fast, precise and stable measurements continuously over a few meters of axis-travel. Test results show that the proposed interferometer proves itself as a potential candidate of absolute-type position transducer needed for next-generation ultra-precision machine axis control, demonstrating linear errors of less than 61.9 nm in peak-to-valley over a 1-meter travel with an update rate of 100 Hz when compared to an incremental-type He-Ne laser interferometer.
authors.forename: Guochao
authors.initials: G
authors.lastname: Wang
authors.forename: Yoon-Soo
authors.initials: YS
authors.lastname: Jang
authors.forename: Sangwon
authors.initials: S
authors.lastname: Hyun
authors.forename: Byung Jae
authors.initials: BJ
authors.lastname: Chun
authors.forename: Hyun Jay
authors.initials: HJ
authors.lastname: Kang
authors.forename: Shuhua
authors.initials: S
authors.lastname: Yan
authors.forename: Seung-Woo
authors.initials: SW
authors.lastname: Kim
authors.forename: Young-Jin
authors.initials: YJ
authors.lastname: Kim