Young's Double Slit Experiment

Factual Questions
1

I am trying to get Young’s double slit experiment (a demo of a pattern formed by shining a laser through two closely spaced slits) with a small laser pointer. The pointer is class IIIA (really low power) and is red.

Although I have done this with another laser with a between slit distance as wide as .7mm (mechanical pencil lead), I can’t seem to get any pattern with this pointer. All I can see is an outline of the two slits.

Any suggestions as to what might be going wrong?

2

Try reflecting it off a CD onto a wall

3

The light from a diode laser is strongly linearly polarized. In order for the experiment to be successful the plane of polarization must be parallel to the orientation of the slits. Try rotating your pointer while running the experiment.

4

Thanks, QED, your suggestion to rotate worked.

5

No problem. Glad you got it working!