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 ?