Register to reply

3 Photons going through 3 Polarizers

by JoshWard
Tags: polarizer photon
Share this thread:
Mar1-12, 04:26 PM
P: 1
1. The problem statement, all variables and given/known data
Suppose we set up a sequence of three polarizers with orientations 45 degrees, 75 degrees and 45 degrees, where the angles refer to how much each polarizer is rotated relative to the vertical direction.

If we send three vertically (i.e. 0 degrees) polarized photons in either 0, 1, 2, or 3 photons might pass through all the polarizers. What is the probability for each of these possibilities?

2. Relevant equations

lθ> = cos(θ)l0 degrees> + sin(θ)l90 degrees> (Dirac Notation)
Probability = cos^2(θ)

3. The attempt at a solution

Well what I have is that when the photons go through the first polarizer, the probability of 1 getting through is 50%, 25% for 2 and so on. Then the photons become polarized at 45 degrees. I'm just having a hard time figuring out how to continue through the 75 degrees polarizer and the last 45 degree polarizer. All I want to know is how to set up the photons going through the 75 degree polarizer, from there I can get the rest.
Phys.Org News Partner Science news on
NASA team lays plans to observe new worlds
IHEP in China has ambitions for Higgs factory
Spinach could lead to alternative energy more powerful than Popeye
Mar2-12, 04:38 AM
Sci Advisor
HW Helper
PF Gold
P: 11,672
When you say the probability is equal to ##\cos^2 \theta##, what exactly does ##\theta## represent? If you understand that, how to deal with the second polarizer is straightforward.

Register to reply

Related Discussions
Three Polarizers Quantum Physics 8
Photons and Polarizers? Quantum Physics 3
Homework on polarizers Introductory Physics Homework 4
Three polarizers Advanced Physics Homework 1
Find the final percentage of light exiting the last polizer General Physics 2