title: Method for measuring the refractive index and the thickness of transparent plates with a lateral-shear, wavelength-scanning interferometer.
abstract: A new method for measuring simultaneously the thickness and the refractive index of a transparent plate is proposed. The method is based on a simple, variable lateral-shear, wavelength-scanning interferometer. To achieve highly accurate measurements of both refractive index n and thickness d we use several means to determine these two quantities. We finely tune a distributed-feedback diode laser light source to introduce a phase shift into the detected signal, whereas we make the sample rotate to produce variable lateral shearing. Phase shifting permits precise determination of the optical thickness, nd, whereas refractive index n is obtained from the retrieved phase of the overall interference signal for all incidence angles.
authors.affiliation: Istituto per la Microelettronica e i Microsistemi, del Consiglio Nazionale delle Ricerche, Sezione di Napoli, Via P. Castellino, 111, 80131 Naples, Italy. giuseppe.coppola@imm.cnr.it
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Coppola
authors.forename: Pietro
authors.initials: P
authors.lastname: Ferraro
authors.forename: Mario
authors.initials: M
authors.lastname: Iodice
authors.forename: Sergio
authors.initials: S
authors.lastname: De Nicola