Main Question or Discussion Point
Is there any way to perform the double slit experiment and see the interference pattern without using a laser? If so, what type of light do you need?
What do you mean by chromatic?As far as I understand it- the light need not be chromatic at all.
Right. We do it by using a semi-transparent "diffuser" screen as the final target, and looking at the back side, in the direction of the slits and the light source. If you turn out the room lights and block stray light from the source, you can easily get a dim but clearly visible interference pattern that's perhaps a centimeter wide. Our initial collimating slit is 0.1 mm wide, and we use a small high-intensity desk lamp as the light source, with a clear-glass bulb so the filament makes for a fairly small source already.As for how to do it.. collimate the light by letting it pass through a very narrow gap (say, between two razor blades). Then have it go through another such gap, or your double slit perhaps. You may need some kind of lens to appreciate the pattern. Works fine with a normal battery torch.. well.. actually it's a pain because you likely need a dark room to be able to see the small amount of light involved, and you need to block out the extra torchlight.. it's fiddly.