Optics Express · 2015 · 34 citations · 11 references
Natural SciencesMaterials EngineeringMaterials ScienceMaterials CharacterizationMetrologyOpticsInterferometryMechanical MeasurementOptical MetrologyPhysical OpticsRefractive IndexVibration MeasurementGroup Refractive IndexInterferometer DesignInterferometric MeasurementInterferometric MetrologyMach-zehnder InterferometersOptical InterferometryOptical Thickness MeasurementVibration-insensitive Metrology
We propose and realize a modified spectral-domain interferometer to measure the physical thickness profile and group refractive index distribution of a large glass substrate simultaneously. The optical layout was modified based on a Mach-Zehnder type interferometer, which was specially adopted to be insensitive to mechanical vibration. According to the measurement results of repeated experiments at a length of 820 mm along the horizontal axis, the standard deviations of the physical thickness and group refractive index were calculated to be 0.173 μm and 3.4 × 10(-4), respectively. To verify the insensitivity to vibration, the physical thickness values were monitored at a stationary point while the glass panel was swung at an amplitude exceeding 20 mm. The uncertainty components were evaluated, and the combined measurement uncertainty became 161 nm (k = 1) for a glass panel with a nominal thickness of 0.7 mm.
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