Unpolarized light of intensity I 0 is incident upon a stack of N+1 ideal polariz

Question

Unpolarized light of intensity I0 is incident upon a stack of N+1 ideal polarizing sheets. The sheets are all parallel to the x-y plane, and the light wave is traveling in the +z direction. Each sheet is rotated by an angle of pi/2N radians counter-clockwise with respect to the preceding sheet, as viewed from the perspective of the light wave. The transmission axis of the first sheet is parallel to the x-axis.

a) What is the intensity of the light after it passes through the first sheet? What is its polarization vector?

b) What is the intensity of the light after it passes through the second sheet?

c) What is the intensity of the light and its polarization vector after it passes through the last sheet? What is the limiting value of this intensity as the number of sheets gets very large?

d) What is the intensity of the final transmitted light if I0 =____W/m2 and N=____?

Solve using variable rather than numbers.

Explanation / Answer

a) I1 = Io/2

(b)

N = 2

I2 = I1*(costheta)^2

I2 = I1*( cos(pi/2N) )^2    <<------answer

c)

Each time the light passes through a polarizer its intensity will decrease by (cos)^2, where = /2N.

There are N+1 polarizers, and the first one just decreased the initial intensity by half,

I = (Io/2)* (cos(/2N))^2N

As N goes to infinity the angle goes to zero and cosine goes to one.

Then I=Io/2

Related Questions

Navigate

• Browse (All)
• Browse U
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.