How does light passing through a QWP become unpolarized?

Thread starter CH1991
Start date Dec 14, 2011
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Polarizer

AI Thread Summary

Light passing through a quarter-wave plate (QWP) can become unpolarized due to the phase shift it introduces, which affects the polarization state of the light. When light encounters a polarizer, only a portion passes through, typically calculated using Malus's law, which states that the intensity of transmitted light is proportional to the cosine squared of the angle between the light's polarization direction and the polarizer's axis. The discussion suggests that the intensity of light after passing through two polarizers can be calculated as 0.5 * 0.5 = 0.25, indicating that half the light intensity is lost at each polarizer. The QWP's role in altering the polarization state is crucial for understanding how the light becomes unpolarized. Overall, the interaction of light with polarizers and the QWP leads to a reduction in intensity and changes in polarization.

Dec 14, 2011

CH1991

Homework Statement

http://i.imgur.com/awJgh.png

Homework Equations

The Attempt at a Solution

Is just because lights out of QWP become unpolarized so 0.5*0.5 = 0.25?
Thanks!

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Dec 14, 2011

Spinnor

Gold Member

Half the light makes it past the first polarizer, to figure out how much gets past the second see,

http://en.wikipedia.org/wiki/Polarizer#Malus.27_law_and_other_properties

Hope this helps.

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