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Finding polarization of a laser


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Hi, I'm new to this forum, and I need some help with this.

I want to determine the polarization of a laser beam, that is, the type of polarization (linear, elliptical), the angle of polarization (if it is linear). Then, I want to represent this mathematically.

I used some linear polarizers to find the polarization of the laser, passing the laser beam through the polarizer to a wall. I found the angle in which the laser light was more intense (bright) on the wall, and then started spinning it slowly, wanting to find the angle in which the intensity after the polarizer was zero (90º from the brightest angle). However, there was no point in which there was no light behind the polarizer. So I thought the polarization had to be elliptical.

I also tried to find Brewster's angle, but there was no angle without reflection, so I confirmed the laser beam is not linearly polarized.


Getting to the point, I have a photometer so I can determine the intensity of the laser beam at certain angles, but how, with that information, can I represent the polarization that I have? Is this method OK, or, what method should I follow so as to get relevant information? Some webpages (such as this one: http://en.wikipedia.org/wiki/Elliptical_polarization) say how this is done, but I sometimes don't know what each letter means since it is not always clarified?

Please someone help me, I'll really appreciate it. Thanks in advance.


(Please if you quote any webpage please let me know the source, and excuse my writing, English is not my native language)

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I have few lasers, and none has linear polarization.

If you have polarization filter, you can find out yours LED/LCD/mobile phones screens polarization.
See this thread how I am doing so:
http://www.scienceforums.net/topic/80366-particle-location/page-3#entry783255
Modern mobile phones that I checked have screens emitting not linearly polarized light.

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The polarization could be worse than elliptic. The laser can perfectly emit light whose polarization hops randomly over time. For instance if gas molecules of random orientation lase, and no mirror nor polarizer forces the polarization within the cavity, then it looks just logical.

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