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Bruns S, Henning P, Melzig T, Terhürne J, Vergöhl M. Improving optical thickness monitoring by including systematic and process-influenced transmittance deviations. APPLIED OPTICS 2023; 62:B141-B147. [PMID: 37132899 DOI: 10.1364/ao.475076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
During optical monitoring using broadband transmittance measurement, the accuracy depends on how both the substrate and the optical path are aligned. We present a correction procedure to improve the accuracy of the monitoring, even if the substrate has features such as absorption or if there is misalignment of the optical path. The substrate in this case can either be a test glass or a product. The algorithm is proven by experimental coatings which were produced with and without the correction. Additionally, the optical monitoring system was also used to perform an in situ quality check. The system allows a detailed spectral analysis of all substrates with a high position resolution. Both plasma and the temperature effects on the central wavelength of a filter are identified. This knowledge enables the optimization of the following runs.
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Optical Properties and Stability of Copper Thin Films for Transparent Thermal Heat Reflectors. METALS 2022. [DOI: 10.3390/met12020262] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The use of thin metallic layers at the thickness limit where transparency or spectral selectivity are achieved is gaining increased interest. The use of cheap and abundant materials is desirable in the attempt to avoid environment or economical costs. The use of Cu as a replacement for Ag as a heat reflector is one of the solutions that can be employed. The stability over time is a known issue, copper being prone to atmospheric oxidation and degradation. In this contribution, the stability of Cu obtained by magnetron sputtering is investigated, using both DC and HiPIMS processes for obtaining the Cu thin films. The bias voltage is used to obtain thin films with different properties, their time stability being investigated through the variation of spectrophotometric curves. The best performing thin films are evaluated in theoretical heat reflector structures, using SiNx of different qualities as dielectric layers to form the dielectric/metal/dielectric structure.
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Amotchkina TV, Trubetskov MK, Tikhonravov AV, Janicki V, Sancho-Parramon J, Razskazovskaya O, Pervak V. Oscillations in spectral behavior of total losses (1 - R - T) in thin dielectric films. OPTICS EXPRESS 2012; 20:16129-16144. [PMID: 22772303 DOI: 10.1364/oe.20.016129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We explain reasons of oscillations frequently observed in total losses spectra (1 - R - T) calculated on the basis of measurement spectral photometric data of thin film samples. The first reason of oscillations is related to difference in angles of incidence at which spectral transmittance and reflectance are measured. The second reason is an absorption in a thin film. The third reason is a slight thickness non-uniformity of the film. We observe a good agreement between theoretical models and corresponding measurements, which proves above statements on the origins of oscillations in total losses.
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Affiliation(s)
- Tatiana V Amotchkina
- Research Computing Center, Moscow State University, Leninskie Gory, 119991, Moscow, Russia.
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Amotchkina TV, Trubetskov MK, Pervak V, Schlichting S, Ehlers H, Ristau D, Tikhonravov AV. Comparison of algorithms used for optical characterization of multilayer optical coatings. APPLIED OPTICS 2011; 50:3389-3395. [PMID: 21743545 DOI: 10.1364/ao.50.003389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Two algorithms used for the on-line and off-line characterization of multilayer optical coatings are experimentally compared using test samples produced by two different deposition processes and different monitoring approaches. One of these algorithms, called the triangular algorithm, demonstrates its superiority in all considered situations. We performed experiments with multilayer samples formed by high-density thin films, which allowed us to neglect possible errors in the film refractive indices and concentrate only on errors in the thicknesses of the layers of the produced coatings.
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Affiliation(s)
- Tatiana V Amotchkina
- Research Computing Center, Moscow State University, Leninskie Gory, 119992, Moscow, Russia
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Tikhonravov AV, Trubetskov MK, Amotchkina TV. Investigation of the error self-compensation effect associated with broadband optical monitoring. APPLIED OPTICS 2011; 50:C111-C116. [PMID: 21460924 DOI: 10.1364/ao.50.00c111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A rigorous definition of the error self-compensation effect is provided. An existence of this effect in the case of coating production with broadband optical monitoring of layer thicknesses is investigated for several widely used types of optical coatings.
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Tikhonravov AV, Trubetskov MK, Amotchkina TV, DeBell G, Pervak V, Sytchkova AK, Grilli ML, Ristau D. Optical parameters of oxide films typically used in optical coating production. APPLIED OPTICS 2011; 50:C75-C85. [PMID: 21460986 DOI: 10.1364/ao.50.000c75] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Wavelength dependencies of refractive indices of thin film materials differ for various deposition conditions, and it is practically impossible to attribute a single refractive index wavelength dependence to any typical thin film material. Besides objective reasons, differences in the optical parameters of thin films may also be connected with nonadequate choices of models and algorithms used for the processing of measurement data. The main goal of this paper is to present reliable wavelength dependencies of refractive indices of the most widely used slightly absorbing oxide thin film materials. These dependencies can be used by other researchers for comparison and verification of their own characterization results.
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Wilbrandt S, Stenzel O, Kaiser N. All-oxide broadband antireflection coatings by plasma ion assisted deposition: design, simulation, manufacturing and re-optimization. OPTICS EXPRESS 2010; 18:19732-19742. [PMID: 20940868 DOI: 10.1364/oe.18.019732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A new all-oxide design for broadband antireflection coatings with significantly reduced impact of deposition errors to the final reflectance is presented. Computational manufacturing including re-optimization during deposition has been used in the design work to account for maximum insensibility of the design with respect to deposition errors typical for plasma ion assisted deposition PIAD. Repeated deposition runs with the deducted monitoring and re-optimization strategy verify the validity of the simulations and the stability of the derived design solution.
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Affiliation(s)
- Steffen Wilbrandt
- Fraunhofer-Institute for Applied Optics and Precision Engineering IOF, Jena, Germany.
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Friedrich K, Wilbrandt S, Stenzel O, Kaiser N, Hoffmann KH. Computational manufacturing of optical interference coatings: method, simulation results, and comparison with experiment. APPLIED OPTICS 2010; 49:3150-3162. [PMID: 20517386 DOI: 10.1364/ao.49.003150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Virtual deposition runs have been performed to estimate the production yield of selected oxide optical interference coatings when plasma ion-assisted deposition with an advanced plasma source is applied. Thereby, deposition of each layer can be terminated either by broadband optical monitoring or quartz crystal monitoring. Numerous deposition runs of single-layer coatings have been performed to investigate the reproducibility of coating properties and to quantify deposition errors for the simulation. Variations of the following parameters are considered in the simulation: refractive index, extinction coefficient, and film thickness. The refractive index and the extinction coefficient are simulated in terms of the oscillator model. The parameters are varied using an apodized normal distribution with known mean value and standard deviation. Simulation of variations in the film thickness is performed specific to the selected monitoring strategy. Several deposition runs of the selected oxide interference coatings have been performed to verify the simulation results by experimental data.
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Affiliation(s)
- Karen Friedrich
- Fraunhofer Institut für Angewandte Optik und Feinmechanik (IOF), Albert-Einstein-Strasse 7, D-07745 Jena, Germany
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Amra C, Deumié C, Georges G, Grèzes-Besset C, Chazallet F. Efficiency of polarimetric z probing in optical multilayers. APPLIED OPTICS 2008; 47:C279-C283. [PMID: 18449259 DOI: 10.1364/ao.47.00c279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Numerical calculation is performed to validate the principles of a single optical technique devoted to real time probing or imaging of submultilayers within interferential coatings.
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Affiliation(s)
- Claude Amra
- Institut Fresnel, Unité Mixte de Recherche, Centre National de la Recherche Scientifique T2I 6133,Université Paul Cézanne, Université de Provence,Faculté des Sciences et Techniques de St Jérôme, Marseille Cedex 20, France.
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Wilbrandt S, Stenzel O, Kaiser N, Trubetskov MK, Tikhonravov AV. In situ optical characterization and reengineering of interference coatings. APPLIED OPTICS 2008; 47:C49-C54. [PMID: 18449271 DOI: 10.1364/ao.47.000c49] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A new optical monitoring system has been developed that allows recording of transmission spectra in the wavelength range between 400 and 920 nm of a growing optical coating during deposition. Several kinds of thin film sample have been prepared by use of a hybrid monitoring strategy that is essentially based on a combination of quartz monitoring and in situ transmission spectra measurements. We demonstrate and discuss the applicability of our system for reengineering procedures of high-low stacks and measurements of small vacuum or thermal shifts of optical coatings.
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Affiliation(s)
- Steffen Wilbrandt
- Fraunhofer Institute of Applied Optics and Precision Engineering, Albert-Einstein-Strasse 7, D-07745 Jena, Germany.
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Tikhonravov AV, Trubetskov MK, Amotchkina TV. Investigation of the effect of accumulation of thickness errors in optical coating production by broadband optical monitoring. APPLIED OPTICS 2006; 45:7026-34. [PMID: 16946781 DOI: 10.1364/ao.45.007026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We present a theoretical approach enabling one to perform a preproduction investigation of the effect of accumulation of thickness errors in the course of optical coating production using broadband optical monitoring. On the basis of this approach we investigate and compare thickness errors that may be associated with such factors as random and systematic errors in measurement data, instabilities of deposition rates, and inaccuracies of on-line algorithms predicting termination instants for layer depositions.
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Amra C, Deumie C. Z-probing of optical multilayers: theory. OPTICS LETTERS 2006; 31:2704-6. [PMID: 16936864 DOI: 10.1364/ol.31.002704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
A single optical technique is presented that allows direct and selective probing or imaging in the thickness of multilayers. It is based on tunable interferences of polarized light. Adequate vertical resolution is provided with this method.
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Affiliation(s)
- Claude Amra
- Institut Fresnel Marseille, UMR CNRSTIC, Université Paul Cézanne, Ecole Génealiste Ingénieurs Marseille, Cedex, France.
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Lamminpää A, Nevas S, Manoocheri F, Ikonen E. Characterization of thin films based on reflectance and transmittance measurements at oblique angles of incidence. APPLIED OPTICS 2006; 45:1392-6. [PMID: 16539241 DOI: 10.1364/ao.45.001392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The optical parameters of a SiO2 thin-film coating determined from the spectral reflectance and transmittance measurements at various incidence angles, including the normal incidence and the Brewster's angle, are compared in this paper. The high-accuracy measurements were carried out through visible-near-infrared spectral regions by using our purpose-built instruments. The optical parameters obtained from the reflectance and the transmittance data are consistent over the angles of incidence and agree within 0.2%. The effect of important systematic factors in the oblique-incidence spectrophotometric measurements is also discussed.
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Affiliation(s)
- Antti Lamminpää
- Metrology Research Institute, Helsinki University of Technology, P.O. Box 3000, FI-02015 TKK, Finland.
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