dorsal/arxiv
View SchemaA simple method for the determination of slowly varying refractive index profiles from in situ spectrophotometric measurements
| Authors | Daniel Poitras, Ludvik Martinu |
|---|---|
| Categories | |
| ArXiv ID | physics/9804006 |
| URL | https://arxiv.org/abs/physics/9804006 |
| DOI | 10.1364/AO.37.004160 |
Abstract
Reliable control of the deposition process of optical films and coatings frequently requires monitoring of the refractive index profile throughout the layer. In the present work a simple in situ approach is proposed which uses a WKBJ matrix representation of the optical transfer function of a single thin film on a substrate. Mathematical expressions are developed which represent the minima and maxima envelopes of the curves transmittance-vs-time and reflectance-vs-time. The refractive index and extinction coefficient depth profiles of different films are calculated from simulated spectra as well as from experimental data obtained during PECVD of silicon-compound films. Variation of the deposition rate with time is also evaluated from the position of the spectra extrema as a function of time. The physical and mathematical limitations of the method are discussed.
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"abstract": "Reliable control of the deposition process of optical films and coatings\nfrequently requires monitoring of the refractive index profile throughout the\nlayer. In the present work a simple in situ approach is proposed which uses a\nWKBJ matrix representation of the optical transfer function of a single thin\nfilm on a substrate. Mathematical expressions are developed which represent the\nminima and maxima envelopes of the curves transmittance-vs-time and\nreflectance-vs-time. The refractive index and extinction coefficient depth\nprofiles of different films are calculated from simulated spectra as well as\nfrom experimental data obtained during PECVD of silicon-compound films.\nVariation of the deposition rate with time is also evaluated from the position\nof the spectra extrema as a function of time. The physical and mathematical\nlimitations of the method are discussed.",
"arxiv_id": "physics/9804006",
"authors": [
"Daniel Poitras",
"Ludvik Martinu"
],
"categories": [
"physics.optics"
],
"doi": "10.1364/AO.37.004160",
"title": "A simple method for the determination of slowly varying refractive index profiles from in situ spectrophotometric measurements",
"url": "https://arxiv.org/abs/physics/9804006"
},
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