Photon collisions: CLass 1 laser in mid air?

[Erina]

I am looking to find a way to make two harmless Class 1 lasers collide to create a dot in mid air. My theory (completely un-scientific you understand) is that a laser will carry on forever until it's stopped, but that at Class 1 the beam (body) itself is invisible from the naked eye without particulates. However the dot is always seen, this of course when hitting an object that absorbs light. My theory was that if I could collide two lasers then they would be cut off and as they strike would form a dot in mid air.

 

Now, I've been told that photos do no such thing, no collision and thus no mid air exposure. I've not tried it myself as I only have one red dot Class 1 laser, shame. But, I was looking at this:

 

 

"Delbrück scattering, the deflection of high-energy photons in the Coulomb field of nuclei as a consequence of vacuum polarization has been observed. However, the process of scattering of light by light, has not been observed.[1] In both cases, it is a process described by Quantum Electrodynamics (QED)."

 

ref: http://en.wikipedia.org/wiki/Delbruck_scattering

 

AND some bits and bobs on "Using High-Power Lasers for Detection of Elastic Photon-Photon Scattering"

 

ref: http://www.2physics.com/2006/03/photon-photon-scattering.html

 

 

and so was wondering what people thought here. I am open to alternatives, lasers which can emit something other than photos that can be seen by the naked eye, are safe and generally achieve what I am looking for.

 

Thanks.

[Cap'n Refsmmat]

If you take two lasers which independently are not powerful enough to be visible in air and let their beams cross, the spot at which they cross may be sufficiently bright as to be visible, since you're combining two beams. The beams will not stop at that point, however, but will continue traveling onward.