title: Shearing interference microscope for step-height measurements.
abstract: A shearing interference microscope using a Savart prism as the shear plate is proposed for inspecting step-heights. Where the light beam propagates through the Savart prism and microscopic system to illuminate the sample, it then turns back to re-pass through the Savart prism and microscopic system to generate a shearing interference pattern on the camera. Two measurement modes, phase-shifting and phase-scanning, can be utilized to determine the depths of the step-heights on the sample. The first mode, which employs a narrowband source, is based on the five-step phase-shifting algorithm and has a measurement range of a quarter-wavelength. The second mode, which adopts a broadband source, is based on peak-intensity identification technology and has a measurement range up to a few micrometres. This paper is to introduce the configuration and measurement theory of this microscope, perform a setup used to implement it, and present the experimental results from the uses of the setup. The results not only verify the validity but also confirm the high measurement repeatability of the proposed microscope.
authors.affiliation: Department of Electro-optical Engineering, National Taipei University of Technology, Taipei City, Taiwan.
authors.forename: Hưng-Xuân
authors.initials: HX
authors.lastname: Trịnh
authors.affiliation: Department of Electro-optical Engineering, National Taipei University of Technology, Taipei City, Taiwan.
authors.forename: Shyh-Tsong
authors.initials: ST
authors.lastname: Lin
authors.affiliation: Department of Mechanical Engineering, National Taiwan University, Taipei City, Taiwan.
authors.forename: Liang-Chia
authors.initials: LC
authors.lastname: Chen
authors.affiliation: Department of Mechanical Engineering, Lunghwa University of Science and Technology, Taoyuan City, Taiwan.
authors.forename: Sheng-Lih
authors.initials: SL
authors.lastname: Yeh
authors.affiliation: Graduate Institute of Automation Technology, National Taipei University of Technology, Taipei City, Taiwan.
authors.forename: Chin-Sheng
authors.initials: CS
authors.lastname: Chen
authors.affiliation: School of Mechanical Engineering, Hanoi University of Science and Technology, 01 Dai Co Viet Street, Hanoi City, Viet Nam.
authors.forename: Hong-Hai
authors.initials: HH
authors.lastname: Hoang
keywords: Phase-scanning; phase-shifting; shearing interferometer microscope; step-height