{"id":391358,"date":"2024-10-25T09:44:22","date_gmt":"2024-10-25T09:44:22","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/oscillations-appear-in-normalized-reflexion-spectra\/"},"modified":"2024-10-25T09:44:22","modified_gmt":"2024-10-25T09:44:22","slug":"oscillations-appear-in-normalized-reflexion-spectra","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/oscillations-appear-in-normalized-reflexion-spectra\/","title":{"rendered":"Oscillations appear in normalized reflexion spectra"},"content":{"rendered":"<p>&lt;p&gt;Hello! I&#8217;m trying to model a metallic grating coupler to dynamically show the plasmonic effect to my students. It is basically 2D simulation of a unit cell with periodic boundary conditions along the x axis and PML along the y axis. However, some kind of oscillation appears whenever I calculate the reflexion profile. I&#8217;ve checked the knowledge base and followed the advices. Then, I tried the calculation with the energy monitor behind and in front of the source, increasing the FDTD region&#8217;s height, reducing the autoshutodd value to 10^-6 and changing the mesh settings. Unfortunately, the oscillations are still there. Does anyone have any idea on how it is happening? It is not an important matter but it&#8217;s something I&#8217;m curious about because it is a quite straightforward model apparently. I attach some images to illustrate the problem.&lt;\/p&gt;&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/10\/25-10-2024-1729849448-mceclip0.png\" \/><img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/10\/25-10-2024-1729849453-mceclip1.png\" \/>&lt;\/p&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-391358","topic","type-topic","status-publish","hentry","topic-tag-metasurface-1","topic-tag-plasmonics-1"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 4.9.10 - aioseo.com -->\n\t<meta name=\"description\" content=\"Hello! I&#039;m trying to model a metallic grating coupler to dynamically show the plasmonic effect to my students. It is basically 2D simulation of a unit cell with periodic boundary conditions along the x axis and PML along the y axis. However, some kind of oscillation appears whenever I calculate the reflexion profile. I&#039;ve checked\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<link rel=\"canonical\" href=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/oscillations-appear-in-normalized-reflexion-spectra\/\" \/>\n\t<meta name=\"generator\" content=\"All in One SEO (AIOSEO) 4.9.10\" \/>\n\t\t<meta property=\"og:locale\" content=\"en_US\" \/>\n\t\t<meta property=\"og:site_name\" content=\"Ansys Learning Forum | Ansys Innovation Space\" \/>\n\t\t<meta property=\"og:type\" content=\"article\" \/>\n\t\t<meta property=\"og:title\" content=\"Oscillations appear in normalized reflexion spectra | Ansys Learning Forum\" \/>\n\t\t<meta property=\"og:description\" content=\"Hello! I&#039;m trying to model a metallic grating coupler to dynamically show the plasmonic effect to my students. It is basically 2D simulation of a unit cell with periodic boundary conditions along the x axis and PML along the y axis. However, some kind of oscillation appears whenever I calculate the reflexion profile. 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I&#039;m trying to model a metallic grating coupler to dynamically show the plasmonic effect to my students. It is basically 2D simulation of a unit cell with periodic boundary conditions along the x axis and PML along the y axis. However, some kind of oscillation appears whenever I calculate the reflexion profile. 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I'm trying to model a metallic grating coupler to dynamically show the plasmonic effect to my students. It is basically 2D simulation of a unit cell with periodic boundary conditions along the x axis and PML along the y axis. However, some kind of oscillation appears whenever I calculate the reflexion profile. 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I'm trying to model a metallic grating coupler to dynamically show the plasmonic effect to my students. It is basically 2D simulation of a unit cell with periodic boundary conditions along the x axis and PML along the y axis. However, some kind of oscillation appears whenever I calculate the reflexion profile. 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I'm trying to model a metallic grating coupler to dynamically show the plasmonic effect to my students. It is basically 2D simulation of a unit cell with periodic boundary conditions along the x axis and PML along the y axis. However, some kind of oscillation appears whenever I calculate the reflexion profile. 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