Abstract
	             We study the problem of optimizing the imaginary parts $\mathrm{Im}\, \omega$ of quasi-normal-eigenvalues $\omega$ associated with the equation $y'' = -\omega^2 B y $. It is assumed that the coefficient $B(x)$, which describes the structure of an optical or mechanical resonator, is constrained by the inequalities $0 \le b_1 \le B(x) \le b_2 $. Extremal quasi-normal-eigenvalues belonging to the imaginary line ${\mathrm{i}} {\mathbb R}$ are studied in detail. As an application, we provide examples of $\omega$ with locally minimal $|\mathrm{Im}\, \omega|$ (without additional restrictions on $\mathrm{Re}\, \omega$) and show that a structure generating an optimal quasi-normal-eigenvalue on ${\mathrm{i}} {\mathbb R}$ is not necessarily unique.
	          	             Key words: Dissipation frequencies, damped string, layered optical cavity, optimal design, spectral optimization.
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		       Article Information
		       
		       | Title | Overdamped modes and optimization of resonances in
layered cavities | 
		       | Source | Methods Funct. Anal. Topology, Vol. 23 (2017), no. 3, 252-260 | 
		       
		       		       | MathSciNet | MR3707519 | 
		       		       | Milestones | Received 12/05/2017; Revised 31/05/2017 | 
		       | Copyright | The Author(s) 2017 (CC BY-SA) | 
               
                                  Authors Information
		     	   Illya M. Karabash
Institute of Applied Mathematics and Mechanics, National Academy of Sciences of Ukraine, 1 Dobrovolskogo, Slovyansk, 84100, Ukraine
Olga M. Logachova
Siberian State University of Geosystems and Technologies, Department of Higher Mathematics, Institute of Geodesy and Management, 10 Plakhotnogo, Novosibirsk, 630108, Russia 
Novosibirsk State University of Economics and Management, Department of Mathematics and Natural Sciences, 56 Lomonosov str., Novosibirsk, 630099, Russia
Ievgen V. Verbytskyi
National Technical University of Ukraine ”Igor Sikorsky Kyiv Polytechnic Institute”, Department of Industrial Electronics, Faculty of Electronics, 16 Politekhnichna, block 12, Kyiv, 03056, Ukraine
               
                             
               
                              
               
                              Citation Example
               Illya M. Karabash, Olga M. Logachova, and Ievgen V. Verbytskyi, Overdamped modes and optimization of resonances in
layered cavities, Methods Funct. Anal. Topology 23
                  (2017), no. 3, 252-260.
BibTex
@article {MFAT986,
    AUTHOR = {Karabash, Illya M. and Logachova, Olga M. and Verbytskyi, Ievgen V.},
     TITLE = {Overdamped modes and optimization of resonances in
layered cavities},
   JOURNAL = {Methods Funct. Anal. Topology},
  FJOURNAL = {Methods of Functional Analysis and Topology},
    VOLUME = {23},
      YEAR = {2017},
    NUMBER = {3},
     PAGES = {252-260},
      ISSN = {1029-3531},
  MRNUMBER = {MR3707519},
       URL = {https://mfat.imath.kiev.ua/article/?id=986},
}