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- Title
Optical Sensor Methodology for Measuring Shift, Thickness, Refractive Index and Tilt Angle of Thin Films.
- Authors
Nalimov, Anton; Stafeev, Sergey; Kotlyar, Victor; Kozlova, Elena
- Abstract
We propose a simple optical method and device design for the non-contact determination of small shift, thickness, refractive index, and tilt angle of thin films. The proposed sensor consists of a laser light source, a third- or two-order spiral amplitude zone plate with a high numerical aperture, and a CCD camera connected to a computer. It is shown that the third-order zone plate transforms the incident Gaussian beam into a three-petal rotating beam. By measuring the rotation angle of the three-petal intensity distribution, one can measure the following: a minimum shift along the optical axis of about 7 nm (the wavelength is 532 nm), a change in the plate thickness by 3 nm, a change in the tilt angle of the plate by 0.1 degrees, and a change in the refractive index by 0.01.
- Subjects
OPTICAL sensors; REFRACTIVE index; THIN films; NUMERICAL apertures; OPTICAL devices; CCD cameras
- Publication
Photonics, 2023, Vol 10, Issue 6, p690
- ISSN
2304-6732
- Publication type
Article
- DOI
10.3390/photonics10060690