{"id":290791,"date":"2023-06-28T17:49:22","date_gmt":"2023-06-28T17:49:22","guid":{"rendered":"\/forum\/forums\/reply\/290791\/"},"modified":"2023-06-28T17:49:22","modified_gmt":"2023-06-28T17:49:22","slug":"290791","status":"publish","type":"reply","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/290791\/","title":{"rendered":"Reply To: Negative imaginary index in material data- what to interpret?"},"content":{"rendered":"<p>&lt;p&gt;In your case this material SiO2 can be practivally considered as pure dielectric with a given refractive index directly at the geometry tab, instead of using the mutil-coefficent fitting model.&lt;\/p&gt;&lt;p&gt;Secondly, this small negative value is due to fitting error. If you use much smaller &#8220;fit tolerance&#8221; , or larger weight for the imaginery in the &#8220;show advanced&#8221; tab, it can be corrected.&lt;\/p&gt;&lt;p&gt;Thirdly, if such small &#8220;gain&#8221; does not cause simulation diverging or wrong result, it is ok.&lt;\/p&gt;&lt;p&gt;Speaking to &nbsp;negative absorption in RTA analysis, which one is larger than 1? if R or T is larger than one, then the simulation should be modified: https:\/\/optics.ansys.com\/hc\/en-us\/articles\/12614264530323-Transmission-Results-Greater-Than-One&lt;\/p&gt;&lt;p&gt;If both R and T are normal then it is the marial &#8220;gain&#8221; that causes the issue. Choice of #1 is the simpest solution.&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-290791","reply","type-reply","status-publish","hentry"],"aioseo_notices":[],"acf":[],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/replies\/290791","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/replies"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/reply"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/replies\/290791\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=290791"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}