Just small note about the beauty of laser beam image. Laser beam is coherent light- the waves of the light are synchronized. So all theoretical effects of light can be viewed with naked eye. Here is the image of interference- some light is delayed and when the phase of the wave is opposite, the light disappears. Or it is just cool image.
And here is the detail of the image above. It is a pity, that digital camera can’t catch the “holographic” shine of the object.
It is unfocused red laser beam. I used DVD laser and some lenses. As lenses are not centered, the image is mushroom shaped. The current into laser is only ~75mA. Total distance the beam had traveled is about 6 meters. (18 feet)