Comparison of three focus sensors for optical topography measurement of rough surfaces

0511898 - ÚPT 2020 RIV US eng J - Journal Article
Šarbort, Martin - Holá, Miroslava - Pavelka, Jan - Schovánek, P. - Řeřucha, Šimon - Oulehla, Jindřich - Fořt, Tomáš - Lazar, Josef
Comparison of three focus sensors for optical topography measurement of rough surfaces.
Optics Express. Roč. 27, č. 23 (2019), s. 33459-33473. ISSN 1094-4087
R&D Projects: GA MŠMT(CZ) EF16_026/0008460; GA TA ČR TE01020233; GA TA ČR(CZ) TN01000008; GA MŠMT ED0017/01/01; GA MŠMT(CZ) LO1212
Institutional support: RVO:68081731
Keywords : profilometry * stylus * beam
OECD category: Optics (including laser optics and quantum optics)
Impact factor: 3.669, year: 2019
Method of publishing: Open access
https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-27-23-33459&id=422804

The study compares three variants of focus sensors designed for the optical topography measurement of rough surface specimens with submicron accuracy. We present a theoretical analysis of the focus sensor principles and the experimental measurements with a single point laser probe. A low coherent illumination beam was provided by a monochromatic laser source and a rotating diffuser, which reduced the speckles generated by the rough surface. The reflected beam was modulated by three specific optical elements (axicon, double wedge prism, four spherical lenses) realized by a spatial light modulator. A digital camera detected the output intensity patterns that were evaluated by the intensity centroid method. The results showed a good coincidence of the surface profiles obtained by the three sensor variants with the root-mean-square deviations below one micron. We discuss the results obtained for several specimens with various surface roughness and compare the differences between the three focus sensor variants.
Permanent Link: http://hdl.handle.net/11104/0302138