title: Measurement of the induced refractive index in a photothermorefractive glass by a liquid-cell shearing interferometer.
abstract: A liquid-cell shearing interferometer was developed to measure refractive-index variations (delta n) in transparent materials. The cell was filled with a liquid having a matched refractive index. The achieved resolution was better than 1/1000 of a fringe shift and resulted in a delta n measurement sensitivity down to 10(-7) for 1-mm-thick samples. A refractive-index increment in photothermorefractive glass of up to 5 x 10(-6) was observed after UV exposure at 325 nm. A refractive-index decrement of up to 1 x 10(-3) was observed after thermal development of the exposed sample. It was proved that photothermorefractive glass obeys the reciprocity law; i.e., delta n depends on the UV dosage but does not depend on the irradiance.
authors.affiliation: Light Processing and Technologies, Orlando, Florida 32817, USA.
authors.forename: Oleg M
authors.initials: OM
authors.lastname: Efimov
authors.forename: Leonid B
authors.initials: LB
authors.lastname: Glebov
authors.forename: Hervé P
authors.initials: HP
authors.lastname: Andre