[Physics] Making a bright beam of artificial white light

Question

For educational purposes, is there a way to make a narrow bright beam of white light without much equipment and without using the sun as the source?

The collimated beam should be about 2 mm wide for 50cm length and be visible when seen on a white screen in a room with very partial darkness.

The usual way is to use a very strong light bulb (very hot), focus it using a large lens, then select only a dot using a hole, then collimating the outgoing light with another lens, and then a slit to select only a small fraction of it.

This requires a lot of equiment and takes a lot of space.

Is there another way ?

Answer 1

You might be able to circumvent equipment issues with creative use of Fresnel lenses. Here's the path I would create for the light.

1. Strong Flashlight
2. Focusing Fresnel Lens
3. Collimating Fresnel Lens (inverted lens with image at focus). I'd cut this lens to the correct size for the application.
4. Small hole to refine size and parallel light.

Depending on your intensity requirements you might be able to do it with just a flashlight. Fresnel lenses are fairly cheap and can also be found on old equipment. You might also find using a parabolic mirror, like those sold at beauty stores, useful. You can insert one between stages 1 & 2 or between stages 3 & 4 depending on your needs/goals.