Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free.

I want to reproduce this experiment by myself. What I need for this. What parameters of slits and laser/another light source it needs? Is it possible to make DIY-detector?

share|improve this question
The detector could be a whole separate question, especially if you are thinking of building a photomultiplier or something. Honestly, a successful experiment will show itself qualitatively upon visual inspection. If you want a more quantitative analysis, perhaps taking a RAW picture and looking at pixel values will suffice. –  Chris White Feb 15 '13 at 19:24
You might be interested in quantum eraser experiment, that can also be reproduced at home, youtube.com/watch?v=R-6St1rDbzo –  raindrop Feb 16 '13 at 18:18
duplicate or near-duplicate of physics.stackexchange.com/questions/38440/… –  Ben Crowell May 22 '13 at 4:42
I forgot about this possibility making the double-slit: use MS Paint or Inkscape and print them on overhead transparency. –  Noah Sep 23 '13 at 0:12

4 Answers 4

up vote 13 down vote accepted

It's actually quite easy to perform the experiment in the comfort of your own home. The simplest setup I have seen (as depicted in this, and other youtube videos) is to use a laser pointer and pencil lead, but you can certainly be more systematic and cut slits in some opaque material as well.

I would encourage you to experiment to answer the question of how far apart the slits need to be etc., but some basic math behind this is as follows: If the slits are a distance $d$ apart, if the light has wavelength $\lambda$, and if the distance between the slits and the screen is $L$, then the spacing $\Delta y$ between successive fringes on the wall will approximately be $$ \Delta y \approx \frac{\lambda L}{d} $$ So let's say the laser is red so that $\lambda\approx 700 \mathrm{nm}$, the slits are $1\,\mathrm{mm}$ apart, and the screen is $1.5\,\mathrm m$ away from the slits, then we have $$ \Delta y \approx \frac{(700\,\mathrm{nm})(1.5\,\mathrm{m})}{1\,\mathrm{mm}} = 1.05\,\mathrm{mm} $$ So you can actually try this and see if your results agree! (I might actually try this myself come to think of it; thanks for the question!)


share|improve this answer
Gah. You beat me by about a minute. –  Emilio Pisanty Feb 15 '13 at 17:05
Haha...apologies Emilio. –  joshphysics Feb 15 '13 at 17:05
You can also use human hairs to produce at least single-slit diffraction patterns. Two hairs/graphite leads can in principle also do it, through Babinet's principle. –  Emilio Pisanty Feb 15 '13 at 17:07
What's about detector near one slit? –  Robotex Feb 15 '13 at 18:06
I would add from my own experience that cutting slits in an opaque material often produces slits that are not entirely negligible in width (compared to $d$), so there may be a broad single-slit pattern modulating the double-slit pattern that is sought. –  Chris White Feb 15 '13 at 19:21

Absolutely, though the result does depend somewhat upon your definition of "at home".

Simply seeing the interference pattern is as simple as a laser pointer and a few narrow apertures (see the other answer(s))

People have successfully even done single-photon interference at home!

share|improve this answer

Laser pointer, nit comb, bit of cardboard from a cereal box to control the number of slits. Works perfectly!

share|improve this answer

I don't think Robotex's question on "counter" has been answered .

It is more difficult to put a "counter" than to simply cover one of the slits. the counter experiment is more interesting to observe, I think.

If somebody can suggest a home made electron beam, that would be super. great

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.