Paper:

# Measurement Range Expansion of Chromatic Confocal Probe with Supercontinuum Light Source

## Hiraku Matsukuma^{†}, Ryo Sato, Yuki Shimizu, and Wei Gao

Department of Finemechanics, Tohoku University

6-6-01 Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi 980-8579, Japan

^{†}Corresponding author

Confocal probes have been widely adopted in various industries owing to their depth-sectioning effects. A dual-detector differential chromatic confocal probe using a mode-locked femtosecond laser source is proposed herein, and the measurement range expansion of the probe using a supercontinuum light source is discussed. Supercontinuum light has an extremely wide spectrum. A simulation based on wave optics is performed to evaluate the detection sensitivity and measurable range by considering the chromatic aberration of the lens materials. Additionally, an experimental setup is constructed using a supercontinuum light source, and its feasibility is validated. A measurable range of 200 μm is adopted in the experiment, and three-dimensional surface profile measurements are performed. However, the developed confocal probe has not been used for surface topography measurements. Experiments are conducted to verify the performance of the developed probe.

*Int. J. Automation Technol.*, Vol.15 No.4, pp. 529-536, 2021.

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