The first 8 movies are .mov files intended for classroom discussions regarding the basics of quantum mechanics, and are described in our manuscript, "Video recording true single-photon double-slit interference," R.S. Aspden, M.J. Padgett, G. C. Spalding, American Journal of Physics 84, 671 (2016):
1. Heralded Diffraction, collected photon by photon, with single-mode optical fiber used to input light into the heralding detector
2. Heralded Diffraction, collected photon by photon, with multi-mode optical fiber used to input light into the heralding detector
3. Heralded Imaging, collected photon by photon, with single-mode optical fiber used to input light into the heralding detector
4. Heralded Imaging, collected photon by photon, with multi-mode optical fiber used to input light into the heralding detector
5. Ghost Imaging, collected photon by photon, with single-mode optical fiber used to input light into the heralding detector
6. Ghost Imaging, collected photon by photon, with multi-mode optical fiber used to input light into the heralding detector
7. Ghost Diffraction, collected photon by photon, with single-mode optical fiber used to input light into the heralding detector
8. Ghost Diffraction, collected photon by photon, with multi-mode optical fiber used to input light into the heralding detector
Here, the word "ghost" references Einstein's concern over spooky action at a distance, a topic that really seems to generate lively discussion among students. For an introduction, refer to our (open access) manuscript, "Video recording true single-photon double-slit interference," R.S. Aspden, M.J. Padgett, G. C. Spalding, American Journal of Physics 84, 671 (2016)
How do you teach about the kinds of angular momentum discussed in Modern Physics?
A .mov video of our sonic screwdriver is useful for discussions, in the context of an extended wave (which may just as easily be, say, a hydrogen wavefunction of an electron), what orbital angular momentum means (namely, the helicity of the wavefront). For more information, see "The sonic screwdriver: a model system for study of wave angular momentum," G. C. Spalding, C. Démoré, A. Volovick, Z. Yang, Y. Hertzberg, M. MacDonald, A. Cochran, Proceedings SPIE 8097, 8097-58 (2011), or "Mechanical evidence of the orbital angular momentum to energy ratio of vortex beams," C. Démoré, Z. Yang, A. Volovick, S. Cochran, M. MacDonald, G. C. Spalding, Physical Review Letters 108, 194301 (2012).
A .mpg video I made with Vene Garces-Chavez, of optically rotated liquid crystal droplets is useful for discussing spin angular momentum in the context of vector wavefunctions (e.g., photons or electrons).
Spin and orbital angular momentum can be combined to yield planetary motion of
two particles or
more.
I’m excited about our manuscript on "Observation of image pair creation and annihilation from superluminal scattering sources,” M. Clerici, G. C. Spalding, R. Warburton, A. Lyons, C. Aniculaesei, J.M. Richards, J. Leach, R. Henderson, D. Faccio, published as an open access article in Science Advances 2, e1501691 (2016). The next four videos are .mp4 files described in that paper:
1. A wavefront sweeping across an imaging screen where no time reversal is observed.
2. Time reversal due to the fact that the intersection between the wavefront and the imaging screen moves at superluminal speed relative to the detector.
3. Virtual spot pair annihilation associated with the motion of a wavefront across a curved imaging screen, which corresponds to a spot source changing its speed and crossing the boundary between sub- and super-luminal propagation regions.
4. Virtual spot pair creation associated with the motion of a wavefront across an imaging screen with the opposite curvature from the one in the previous example.
In these videos, anything moving to the LEFT is, as students will easily recognize, not doing what the wavefront incident upon the screen actually did; instead, because of simple Time of Flight effects, you are seeing events in TIME REVERSED ORDER. So, anything moving to the left is going backward in time; anything moving to the right is going forward in time.
— The fact that the videos on spot pair creation and annihilation don’t have equal intensities in the stuff going forward in time and the stuff going backward in time is simply a consequence of beam alignment: we didn’t have equal intensities incident on the two halves of the screen.
— Students find it easy to accept these “purely geometric” arguments, and so I use these videos in my teaching, as part of our conversations on Special Relativity, particularly when practicing spacetime diagrams.
Some of Gabe’s materials on tailored wavefronts may also be of interest, e.g., the first part of our review chapter on Holographic Optical Tweezers.
Information about our educationally priced single-photon detector initiative is available on the ALPhA website, and information about Gabe’s (user-friendly, freeware) particle-tracking software, can be accessed from Gabe’s webpage.