How do i create a flat wide laserbeam ?

I need to draw a flat wide laser beam, so not a point laser but, but a flat wide beam of laser light.
So it does the projection of a line, I am after a cycles results similar like what you see in below pictures.
Those pictures where not from cycles but from real world pictures found on the internet.
Its how i would like it to be
flat and with some smoke noise ?
and a projecting light like

I’ve been trying whole day to get this with volume shaders and other light systems, but so far it didn’t look good. Sometimes as with smoke shaders, everyhting behind it became unlighted and not the target of the beam. I also tried an OSL laser sheet shader script, but i couldnt change its orientation, and its also not like the first image shown above, that rather seams a surface trick and doesn’t behave like light…

So far the best looking shader reciept is this one :

( source : )

It does look better then the OSL script, but still it doesnt look like what i showed in picture 1
So how to get that flat beam laser effect ?