Recent content by bknock

Thanks Charles. Good job finding "Diffraction by a Small Circular Aperture" by Marino and Piredda! I completely agree with what you (and the paper!) are saying about the unrealistic edge assumptions used by Kirchhoff's theory. I suppose that the boundary conditions at edges are EVERYTHING at...

Thanks for confirming that there is an anomaly here! If optics theory in textbooks cannot help, my hope is that some experimentalist could just find such a very thin slit and measure the intensity of what should be an almost independent-of-theta diffraction pattern (better yet, map out the...

Let me be more specific. This problem is much more subtle than freshman-level physics, so sorry for not providing the required details. From the Huygens-Fresnel principle, we get (after doing an integral over phases assuming a distant screen) that intensity is proportional to... a2 * sinc2[...

Imagine a single slit with plane light waves incident on it with a screen (ideally far enough from the slits to simplify the math). According to Kirchhoff's diffraction formula, when a very wide slit is doubled, average intensity (averaged over all diffraction angles) doubles, and so does E_peak...

DrDu, you have completely fixed my confusion! Thank you. And thank you Jivesh :)

Excellent! You have definitely helped me remove a bunch of wrong ideas floating around in my head, but I am still confused about something. After you mentioned that ANY boundary creates reflections, I looked at the situation of a free particle on the left where V=0 encountering a potential...

I was curious what a delta-function potential barrier would do to a free (E>0) 1-dimensional particle, so I figured it out. I used V = b δ(x) for the potential energy. I got the expected result that full reflection will occur as |b|→∞ or as E→0. These results make sense intuitively when b>0. My...