I do not know anything about physics but in order to sort my problem out I have been told to look into the impossibility of photon collisions. What I would like to achieve is to take two Class 1 lasers (any wave length you like) and cross the two, in doing so I was hoping that their infinite range would be terminated at the point of contact and that they would appear as a dot in mid air. As I understand it now a light absorbing material would shows the red dot of a laser, which its beam (the body) remains invisible to the naked eye, but that photos do not collide and so there you go. But, I don't like "no"s and so am looking into this: "In a paper entitled "Using High-Power Lasers for Detection of Elastic Photon-Photon Scattering" published in March 3 issue of Physical Review Letters (Vol.96), Physicists from Umeå University, in Umeå, Sweden, and the Rutherford Appleton Lab, England, propose an experiment to explore the vacuum by aiming three powerful laser streams at each other in 3-dimensional space of the Laboratory (This is important because such proposals mooted earlier had the beams all in a single plane). These three beams will merge to produce a fourth stream with a wavelength shorter than any of the input beams." ref: http://www.2physics.com/2006/03/photon-photon-scattering.html Not sure if I'm on the right track, anybody got any advice? Thanks.