polarisation contents: em waves polarisation angle polaroid filters brewster’s angle
Post on 24-Dec-2015
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More than one polarizer:I = Iocos2
Io – incident intensity of polarized lightI – transmitted intensity (W/m2) – angle twixt polarizer and incident angle of polarization
Demo two polarizers
Io½Io (½ Io)cos2
Two polarizers are at an angle of 37o with each other. If there is a 235 W/m2 beam of light incident on the first filter, what is the intensity between the filters, and after the second?
I = Iocos2After the first polarizer, we have half the intensity:I = 235/2 = 117.5 W/m2
and then that polarized light hits the second filter at an angle of 37o:I = (117.5 W/m2) cos2(37o) = 74.94 = 75 W/m2
Brewster’s angle:•non-metallic surface•reflected light polarized parallel to surface.
In generaln2 = tann1
For air (n1 = 1.00) to something:n = tan
demo – small polarizers
I = ?, Io = 120. W/m2, = 21.0o
I = 104.58 W/m2
105 W/m2 W
120. W/m2 of vertically polarized light goes through a filter that makes an angle of 21.0o with the vertical. What is the transmitted intensity?
I = Iocos2
I = 80.0 W/m2, Io = 120. W/m2, = ? = 35.26o
35.3o W
120. W/m2 of vertically polarized light goes through a filter that makes some angle with the vertical such that only 80.0 W/m2 are transmitted. What angle does the filter make with the vertical?
I = Iocos2
After the first filter, we are down to 250 W/m2, Then we use the formula I = Iocos2 = (250 W/m2)cos(68.0o)2 = 35.08 W/m2.
35.1 W/m2 W
500. W/m2 of UNpolarized light goes through a vertically polarized filter, and then through one the makes an angle of 68.0o with the vertical. What is the transmitted intensity?
I = Iocos2
n = ?, = 67.5n = 2.420
2.420 W
What is the index of refraction of a substance that has a Brewster’s angle of 67.55o?
n = tan
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