Thickness measurement of thin transparent plates with a broad-band wavelength scanning interferometer
Year: 2004
Authors: Maddaloni P., Coppola G., De Natale P., De Nicola S., Ferraro P., Gioffrè M., Iodice M.
Autors Affiliation: Istituto Nazionale di Ottica Applicata, Via Campi Flegrei 34, 80078 Pozzuoli (Napoli), Italy;
Istituto per la Microelettronica e Microsistemi-Consiglio Nazionale delle Ricerche, Via P. Castellino 111, 80131 Napoli, Italy;
Istituto di Cibernetica-Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, 80078 Pozzuoli (Napoli), Italy
Abstract: A novel broad-band telecom laser source is used to realize a lateral-shear scanning-wavelength interferometer for measuring the thickness of thin plates. We show that the wide tunability range allows to detect samples down to tens of microns with a relative uncertainty of less than 0.5% and a resolution of about 1 nm. A comparable accuracy in the thickness characterization of double-layer structures is also demonstrated. In turn, the wide tunability range needs the dispersion law of the materials to be taken into account in the model for correct thickness evaluation.
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KeyWords: Cameras; Characterization; Charge coupled devices; Fiber lasers; Radiation; Refractive index; Scanning; Silicon; Spectrophotometry; Dielectric layers; Dispersion; Relative shifts; Thin plates; InterferometersDOI: 10.1117/12.544955Connecting to view paper tab on IsiWeb: Click here