Simultaneous Measurement of Refractive Index and Thickness by Low Coherence Interferometry Considering Chromatic Dispersion of Index

Maruyama, Hideki; Mitsuyama, Teruki; Ohmi, Masato; Haruna, Masamitsu

doi:10.1007/s10043-000-0468-0

Cited by 25 publications

(10 citation statements)

References 12 publications

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“…It could only give an optical path length of a sample since a light consisting of many frequency components propagates through the sample with the form of a wave packet. Many works have been reported to deal with this problem [2][3][4][5] . One of the preferred methods is adding a confocal system to the LCI, which requires at least one more moving part 2, 3 .…”

Section: Introductionmentioning

confidence: 99%

Dual-probe simultaneous measurements of refractive index and thickness with spectral-domain low coherence interferometry

Park

Kim

et al. 2011

SPIE Proceedings

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An optical interferometric system for the simultaneous measurements of physical thickness and refractive group index is implemented. The proposed system is based on a spectral-domain optical low coherence interferometry with two sample probes facing to each other. The two-probe approach enables simultaneous measurements of thickness and group index of a transparent sample. The average measurement errors were ~0.112 % in the physical thickness and ~0.035 % in the group index, respectively.

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Section: Introductionmentioning

confidence: 99%

Dual-probe simultaneous measurements of refractive index and thickness with spectral-domain low coherence interferometry

Park

Kim

et al. 2011

SPIE Proceedings

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“…Confocal scanning is a convenient complementary technique which involves scanning the focused illumination beam through each interface of the sample under test [4]. To acquire all three variables; the phase and group refractive indices and the physical thickness, the low-coherence and confocal measurements need to be combined via a measure of the sample's chromatic dispersion [5]. This can be done by making the confocal measurements at multiple wavelengths.…”

Section: Introductionmentioning

confidence: 99%

The use of parabolic mirrors in combined low-coherence and confocal refractive index measurement

Francis

Ford

Hallam

et al. 2019

Optical Measurement Systems for Industrial Inspection XI

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Low-coherence interferometry is combined with confocal scanning to provide remote refractive index and thickness measurements of transparent materials. The influence of lens aberrations in the confocal measurement is assessed through investigation of the axial point-spread functions (APSFs) generated using optical configurations comprised of paired aspherics and paired achromats. Off-axis parabolic mirrors are suggested as an alternative to lenses and are shown to exhibit much more symmetric APSFs provided the system numerical aperture is not too high. Refractive index and thickness measurements are made with each configuration with most mirror pairings offering better than twice the repeatability and accuracy of either lens pairing.

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“…Several techniques have been reported for simultaneous measurement of refractive index and thickness using an OCT system in both TD and FD. These techniques suitable for single layer objects can be listed in TD as low-coherence reflectometry, [14][15][16][17][18] focus-tracking method, [19][20][21][22][23][24][25][26][27][28][29] bifocal optical coherence refractometry, 30,31 digital refocusing technique, 32,33 and tandem configuration of interferometers for dispersion-insensitive measurements. [34][35][36] In the FD approach, the simultaneous measurement of refractive index and thickness of a single layer object has been reported using a reference plane behind the object, 37,38 providing a step on the object, 39 using a dual sample probe 40 or by fitting a modeled signal to the actual spectrum.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous measurement of refractive index and thickness of multilayer systems using Fourier domain optical coherence tomography, part 1: theory

et al. 2017

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We introduce a theoretical framework for simultaneous refractive index and thickness measurement of multilayer systems using the Fourier domain optical coherence tomography (FD-OCT) system without any previous information about the item under investigation. The input data to the new formalism are the FD-OCT measured optical path lengths and properly selected spectral components of the FD-OCT interference spectrum. No additional arrangement, reference reflector, or mechanical scanning is needed in this approach. Simulation results show that the accuracy of the extracted parameters depends on the index contrast of the sample while it is insensitive to the sample’s thickness profile. For transparent biological samples with smooth interfaces, when the object is in an aqueous medium and has indices < 1.55 , this method can extract indices and thicknesses with the absolute error ? 0.001 .

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Simultaneous Measurement of Refractive Index and Thickness by Low Coherence Interferometry Considering Chromatic Dispersion of Index

Cited by 25 publications

References 12 publications

Dual-probe simultaneous measurements of refractive index and thickness with spectral-domain low coherence interferometry

Dual-probe simultaneous measurements of refractive index and thickness with spectral-domain low coherence interferometry

The use of parabolic mirrors in combined low-coherence and confocal refractive index measurement

Simultaneous measurement of refractive index and thickness of multilayer systems using Fourier domain optical coherence tomography, part 1: theory

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