Abstract
A noncontact displacement system suitable for tracking slow moving surfaces with low reflectivity is demonstrated. The displacement is measured by dynamic tracking of the moving focal plane of the sample under test. The system comprises a camera, a vertical digital piezo driver, and a data acquisition module. The tracking effect is achieved by continuously driving the sample with a 2-μm sweep around the focal plane, simultaneously acquiring the sample position and images of the part of the sample defined as a region of interest (ROI). The position of the focal plane is identified by fitting the contrast of the ROI versus the stage position to a Gaussian function. Using an ROI provides the ability to test various regions across the object and eliminates the demand for the surface to be flat or reflective. The system is low cost, is applicable to a large variety of samples and has an accuracy better than 10 nm.
| Original language | English |
|---|---|
| Article number | 124112 |
| Journal | Optical Engineering |
| Volume | 60 |
| Issue number | 12 |
| DOIs | |
| State | Published - 1 Dec 2021 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2021 Society of Photo-Optical Instrumentation Engineers (SPIE).
Funding
This work was supported by NATO Science for Peace award G5453, and, in part, by the BioWings project, which has received funding from the European Union’s Horizon 2020 under the Future and Emerging Technologies (FET) program with Grant Agreement No. 801267. IL and AIF acknowledge the NSF-BSF program Grant No. 2018717. AIF acknowledges the support by NSF DMR Grant No. 1911592. The authors declare that there are no conflicts of interest.
| Funders | Funder number |
|---|---|
| NATO Science for Peace | G5453 |
| NSF DMR | 1911592 |
| NSF-BSF | 2018717 |
| Horizon 2020 Framework Programme | |
| H2020 Future and Emerging Technologies | 801267 |
Keywords
- contrast auto focusing
- displacement measurement
- slow oscillatory motion