Revision as of 00:31, 4 September 2024 edit Johnjbarton (talk \| contribs) Extended confirmed users 18,001 edits →Complex refractive index: name ref for reuse, add to the defined term with page number. ← Previous edit		Revision as of 00:38, 4 September 2024 edit undo Johnjbarton (talk \| contribs) Extended confirmed users 18,001 edits →Complex refractive index: delete content that does not verify. The MIT course notes say nothing about mass attenuation. Next edit →
Line 173: <math display="block">\underline{n} = n + i\kappa.</math> Here, the real part {{mvar\|n}} is the refractive index and indicates the [[phase velocity]], while the imaginary part {{mvar\|κ}} is called the '''extinction coefficient'''~~<ref name=DresselhausMITCourse/>{{rp\|36}} or ''[[absorption coefficient]]''—although {{mvar\|κ}} can also refer to the [[mass attenuation coefficient]]~~<ref name=DresselhausMITCourse>{{cite web \|url = http://web.mit.edu/course/6/6.732/www/6.732-pt2.pdf \|title = Solid State Physics Part II Optical Properties of Solids Line 186: \|archive-url = https://web.archive.org/web/20150724051216/http://web.mit.edu/course/6/6.732/www/6.732-pt2.pdf \|archive-date = 2015-07-24 }}</ref>{{rp\|336}}~~—and~~ or ''[[absorption coefficient]]'' and indicates the amount of attenuation when the electromagnetic wave propagates through the material.<ref name="Hecht"/>{{rp\|p=128}} That {{mvar\|κ}} corresponds to absorption can be seen by inserting this refractive index into the expression for [[electric field]] of a [[plane wave\|plane]] electromagnetic wave traveling in the {{mvar\|x}}-direction. This can be done by relating the complex [[wave number]] {{mvar\|{{uu\|k}}}} to the complex refractive index {{mvar\|{{uu\|n}}}} through {{math\|{{uu\|''k''}} {{=}} 2π{{uu\|''n''}}/''λ''{{sub\|0}}}}, with {{math\|''λ''{{sub\|0}}}} being the vacuum wavelength; this can be inserted into the plane wave expression for a wave travelling in the {{mvar\|x}}-direction as:

Refractive index: Difference between revisions