Editing Waveplate (section)

=== Full-wave, or sensitive-tint plate ===
A full-wave plate introduces a phase difference of exactly one wavelength between the two polarization directions, for one wavelength of light. In [[optical mineralogy]], it is common to use a full-wave plate designed for green light (a wavelength near 540&nbsp;nm). Linearly polarized white light which passes through the plate becomes elliptically polarized, except for that green light wavelength, which will remain linear. If a linear polarizer oriented perpendicular to the original polarization is added, this green wavelength is fully extinguished but elements of the other colors remain. This means that under these conditions the plate will appear an intense shade of red-violet, sometimes known as "sensitive tint".<ref>{{cite web |url=http://www.doitpoms.ac.uk/tlplib/optical-microscopy/plates.php |title=Tint plates |website=DoITPoMS |publisher=University of Cambridge |access-date=Dec 31, 2016}}</ref> This gives rise to this plate's alternative names, the ''sensitive-tint plate'' or (less commonly) ''red-tint plate''. These plates are widely used in mineralogy to aid in identification of [[mineral]]s in [[thin section]]s of [[rock (geology)|rocks]].<ref name=Winchell121>{{cite book |last1=Winchell |first1=Newton Horace |first2=Alexander Newton |last2=Winchell |title=Elements of Optical Mineralogy: Principles and Methods |volume=1 |location=New York |publisher=John Wiley & Sons |year=1922 |page=121}}</ref>