The line in the air is caused by Rayleigh scattering of a focused beam of light that is a single wavelength or in the case of multimode a single dominate wavelength with adjacent but less intense neighboring wavelengths.
If you want to produce a line rather than a dot on the ground you can use a line lens.
Relight scattering? Check your spelling.:crackup:Just in case some readers don't know what that is:
Rayleigh scattering is the scattering of light or other electromagnetic radiation by particles smaller than the wavelength of the radiation. Named after the British physicist Lord Rayleigh, AKA John William Strutt, this is the same guy that discovered argon, for which he won the Nobel Prize for physics in 1904.
So its a Ray of Light that scatters amongst reflective particles so to speak and I knew part of it, either Ray or Light was different and I guessed backwards. I would have looked it up but, well I didn't, but now I know. However just like when you call Jessica Jennifer just once you get it stuck in your head wrong forever, so I will likely screw it up again. :beer: