Concept of FRET, derived from public domain file <a href="//commons.wikimedia.org/wiki/File:FRET.PNG" title="File:FRET.PNG">File:FRET.PNG</a>.  CFP = cyan fluorescent protein; YFP = yellow fluorescent protein
<a href="//commons.wikimedia.org/wiki/User:Scray" title="User:Scray">Scray</a>
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<span class="int-own-work" lang="en">Own work</span>