Discrete and Continuous Models and Applied Computational ScienceDiscrete and Continuous Models and Applied Computational ScienceDiscrete and Continuous Models and Applied Computational Science2658-46702658-7149Peoples' Friendship University of Russia named after Patrice Lumumba (RUDN University)2518310.22363/2658-4670-2020-28-4-378-397ArticlesСтатьиResearch ArticleSolving the inverse problem for determining the optical characteristics of materialsРешение обратной задачи определения оптических характеристик материаловLovetskiKonstantin P.ЛовецкийК. П.

Candidate of Physical and Mathematical Sciences, assistant professor of Department of Applied Probability and Informatics

lovetskiy-kp@rudn.ruZhukovAndrey A.ЖуковА. А.

PhD, lead analyst of “ITL Consulting” company

a.zhukov@itlc.ruPaukshtoMichael V.ПаукштоМ. В.

- DSc., Physics & Mechanical Engineering, co-founder and CTO of Fibralign Corporation

mpaukshto@fibralignbio.comSevastianovLeonid A.СевастьяновЛ. А.

Doctor of Physical and Mathematical Sciences, professor of Department of Applied Probability and Informatics

sevastianov-la@rudn.ruTiutiunnikAnastasiia A.ТютюнникА. А.

Candidate of Physical and Mathematical Sciences, lecturer of Department of Applied Probability and Informatics

tyutyunnik-aa@rudn.ruPeoples’ Friendship University of Russia (RUDN University)Российский университет дружбы народовITL ConsultingFibralign Corporation15122020284VOL 28, NO4 (2020)ТОМ 28, №4 (2020)37839709122020Copyright ©; 2020, Lovetski K.P., Zhukov A.A., Paukshto M.V., Sevastianov L.A., Tiutiunnik A.A.Copyright ©; 2020, Ловецкий К.П., Жуков А.А., Паукшто М.В., Севастьянов Л.А., Тютюнник А.А.2020Lovetski K.P., Zhukov A.A., Paukshto M.V., Sevastianov L.A., Tiutiunnik A.A.Ловецкий К.П., Жуков А.А., Паукшто М.В., Севастьянов Л.А., Тютюнник А.А.http://creativecommons.org/licenses/by/4.0https://journals.rudn.ru/miph/article/view/25183

The paper describes a methodology for determining the optical and physical properties of anisotropic thin film materials. This approach allows in the future designing multilayer thin-film coatings with specified properties. An inverse problem of determining the permittivity tensor and the thickness of a thin film deposited on a glass substrate is formulated. Preliminary information on the belonging of a thin-film coating to a certain class can significantly reduce the computing time and increase the accuracy of determining the permittivity tensor over the entire investigated range of wavelengths and film thickness at the point of reflection and transmission measurement Depending on the goals, it is possible to formulate and, therefore, solve various inverse problems: o determination of the permittivity tensor and specification of the thickness of a thick (up to 1 cm) substrate, often isotropic; o determination of the permittivity tensor of a thin isotropic or anisotropic film deposited on a substrate with known optical properties. The complexity of solving each of the problems is very different and each problem requires its own specific set of measured input data. The ultimate results of solving the inverse problem are verified by comparing the calculated transmission and reflection with those measured for arbitrary angles of incidence and reflection.

В работе изложена методология определения оптических и физических свойств анизотропных тонкоплёночных материалов. Такой подход позволяет в дальнейшем проектировать многослойные тонкоплёночные покрытия с заданными свойствами. Сформулирована обратная задача определения тензора диэлектрической проницаемости и толщины тонкой плёнки, нанесённой на стеклянную подложку, с известными оптическими свойствами и толщиной. Предварительная информация о принадлежности тонкоплёночного покрытия к определённому классу позволяет значительно сократить время расчёта и увеличить точность определения тензора диэлектрической проницаемости на всём исследуемом интервале длин волн и толщины плёнки в точке измерения отражения и пропускания. В зависимости от поставленных целей возможна постановка и, следовательно, решение различных обратных задач: o определение тензора диэлектрической проницаемости и уточнение толщины толстой (до 1 см) подложки, часто изотропной; o определение тензора диэлектрической проницаемости тонкой изотропной или анизотропной плёнки, нанесённой на подложку, с известными оптическими свойствами. Сложность решения каждой из задач весьма различна и каждая требует своего определённого набора измеренных входных данных. Окончательные результаты решения обратной задачи верифицируются с помощью сравнения вычисленных коэффициентов пропускания и отражения с измеренными для произвольных углов падения и отражения.

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