An interesting way to get an interference pattern

[Igottaknow]

OK so before I begin I will ask that you forgive me because I do not have a working knowledge of the mathematics involved here and I am admittedly not even at a novice level of understanding these things. However I have done at least some research and understand how an interference pattern does emerge when passing light through two slits.

I made a video that shows an interference pattern emerge in a totally different way and i need some help in understanding why. Please watch this video in the highest resolution possible, preferably in 1080p. Also please disregard what I am saying in the video because I would like to keep the focus on why this pattern emerges rather than the terrible science being done in it. I also encourage you to try this yourself so that you can see the pattern with your eye rather than in my video. Plus it is super easy. This does not work with all screens and not all screens produce the same pattern that you will see here. This does however work with any type of light you use (or that I have used). Thank you in advance and I hope you enjoy.

 

[spoirier]

I think you made the right guess at the end of your video already : it's the pixels, the dense periodic succession of vertical lines in the structure of the screen. You can find more detailed explanations in the wikipedia article "Diffraction grating".

An interference from 2 slits, alternates fat zones of light with thin zones of dark. Well this description is just the effect of an optical illusion as the intensity curve is in fact a sinusoid, but the eye feels more contrast for the same luminosity variation when it takes place in the dark than in the light.

But the interference resulting from a periodic system, is thin peaks of light separated by relatively large margins of dark, which is what we observe on screens.

 

[Igottaknow]

Thank you for the response and for watching my video. I read that article before posting this video and searched through images of diffraction grating and did not see much that resembled the same pattern as I was getting here. In most of the examples that you see it is light passing through a screen rather than light reflecting off of a screen.

I found it really interesting that you get the same effect whether the laptops screen is on or off and the light coming from the screen itself has no effect at all on the pattern you get other than making it slightly more difficult to see.

 

[Borek]

You should be able to see similar difference pattern by reflecting the light from the laser diode from CD surface.

 

[sardar]

Thank you for sharing your video and your interest in understanding the interference pattern that emerges in a different way. It is always exciting to see unique and creative ways of demonstrating scientific concepts.

From watching your video, it appears that you are using a diffraction grating or a similar device that splits light into multiple beams. This is similar to the setup of a double-slit experiment, where light passes through two slits and creates an interference pattern on a screen.

In your setup, the light is being split into multiple beams, each with a slightly different angle. When these beams overlap, they create an interference pattern due to the principle of superposition, where the waves either reinforce or cancel each other out.

While the exact mathematics behind your setup may differ from a traditional double-slit experiment, the underlying principle of interference remains the same. It is also worth noting that your setup may produce a different pattern depending on the type of light used, as different wavelengths of light will diffract at different angles.

I would encourage you to continue exploring this concept and perhaps even try to incorporate some mathematical understanding to further explain the phenomenon you have observed. Keep up the curiosity and keep experimenting!