Recent content by Blanchdog

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    Characterizing an unknown eliptical polarization

    In reality I don't have access to the lab thanks to covid, so I was told that the exiting beam is linearly polarized at +12 degrees when the waveplate is rotated to +70 degrees. I tried plugging these numbers in but got back a complex number for the first component in the Jones vector, when it...
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    Orientation of Major Axis for polarized light

    How can I tell the handedness?
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    Orientation of Major Axis for polarized light

    I believe I figured it out, though I would love confirmation. Since ##cos(\delta) = cos(\frac{\pi}{2})=0## and ## A = B##, we end up with ## E_\alpha = E_{\alpha_\pm+\frac{pi}{2}}##. That means we have circularly polarized light! So of course ##\alpha## is undefined; a circle has no determined axes!
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    Orientation of Major Axis for polarized light

    Case 1 worked out great, I found it to be linearly polarized light at an angle ##\alpha = \frac{\pi}{4}##, but Case 2 is giving me trouble. As best I can tell, ##\alpha## is undefined in case 2. How do I solve case 2?
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    Show that the solutions to the Fresnel Equation are real and positive

    Ah I see the issue, I have a typo. The expression I simplified it to should be $$B^2-4AC=\frac{4}{9}(n_x^4 n_y^4 + n_x^4 n_z^4 + n_y^4 n_z^4 - n_x^4 n_y^2 n_z^2 - n_x^2 n_y^4 n_z^2 - n_x^2 n_y^2 n_z^4)$$ This expression is invariate under a cyclic permutation, and I can show 2 of the positive...
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    Show that the solutions to the Fresnel Equation are real and positive

    I'm not sure what a cyclic permutation of indices is, but I pretty much figured that my simplification had a mistake. Any chance you can help me find it?
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    Show that the solutions to the Fresnel Equation are real and positive

    I got as far as simplifying the expression to $$\frac{4}{9}(n_x^4 n_y^4 + n_x^4 n_z^4 + n_y^4 + n_z^4 - n_x^4 n_y^2 n_z^2 - n_x^2 n_y^4 n_z^2 - n_x^2 n_y^2 n_z^4)$$ But that doesn't seem to be a form that is necessarily positive and satisfies the criteria of the homework statement. Little help...
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    Electric Field acting on a point charge

    Electric fields are always continuous, so this cannot be correct. However, if you were to bend the ends of those two lines together at the origin that would pretty much be it. Near the disk the point charge is affected by the disk's presence, it's only further away from the disk that the...
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    Electric Field acting on a point charge

    It isn't, its asymptotic. Essentially as you move further away from the missing disk, the electric field looks more and more just like the field from the charged plane, which is constant.
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    Electric Field acting on a point charge

    Sorry I deleted that because of a mistake, the fraction goes to 1 rather than zero. See post #18.
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    Electric Field acting on a point charge

    You are varying x by some amount, but we know that it will be perfectly mirrored on either side of zero so let's set zero as the lower bound for a plot of what's going on. As mentioned before, E(0) = 0 so that's an easy starting point for your graph. Next, what happens as x becomes large...
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    Electric Field acting on a point charge

    That looks right to me, ignoring the typo on the square root. It would not be a straight line however, as you can see by x appearing in the denominator. Instead, look for something that begins to look like the electric field of the infinite plane as x become large.
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    Electric Field acting on a point charge

    You're right, you're right, I misread (x, 0, 0) as being a point in the plane, not on the x axis. So to amend my earlier statements, at the point (0, 0, 0) the E field and force are both zero, but as the point charge is moved along the x-axis the E field and force acting on it become non zero.
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    Ideal index of refraction for single layer AR coating

    Thanks, that helps a lot with understanding the math of what is going on. I've never encountered a geometric mean in relation to a 'matching' operation though, could you help me understand what the math is describing? As an aside: For two layers of AR coating you would want the second layer to...
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    Electric Field acting on a point charge

    At (x, 0, 0), the force ## F = qE## is indeed zero because ##E = 0## at that point. As one varies the value of x away from zero however, the E field (and thus the force) become non-zero.
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