Thickness measurement of thin transparent plates with a broad-band wavelength scanning interferometer
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.
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