People have used a number of methods to simulate lasers in Pov-Ray. The method I use utilises
emissive media. In Pov-Ray an object can be made transparent, hollow and filled with some kind of
media which simulates a material consisting of many tiny particles, like various gases and smoke.

A laser beam can be seen because laser light is scattered (and also absorbed and re-emitted) from gas
and dust in the path of the laser beam. Thus, it makes sense to me to model a laser beam with emissive
media. A medium given emission emits its own light, simulated in Pov-Ray, and so a cylinder, cone or
elongated sphere that is transparent, hollow and contains an emissive medium can simulate a laser
beam. An example of the laser beam used in the code above is given below:
Battle Drone
Simulating Lasers in Pov-Ray
converging lens
The complete code of this graphic is given below (view here if you can't see the IFrame below):
//Ground laser
difference{
sphere { 0,1 scale <1,1000,1> hollow
pigment { rgbt 1 }
interior
{ media
{ emission 4+4
 density
 { cylindrical density_map
   {
     [ 0 rgb <0, 0, 0> ]
     [ 0.25 rgb <0, 0.4, 0.8> ]
     [ 0.5 rgb <0.2, 0.6, 1> ]
     [ 0.75 rgb <0.6, 0.8, 1> ]
     [ 1.0 rgb <0.6, 1, 1> ]
   }
   turbulence 0.1
   frequency 0.5
  }
}
}
}
cylinder { <0,-980,0>, <0,-1000,0>, 2 }
rotate <0,0,90> translate <-980,13,0> rotate <0,-20-40,0> rotate <-30,0,0>
}
Another example of the use of this type of
laser (left): a space drone firing a laser
beam that has just skimmed over our heads
in the top panel, and has entered the
camera directly in the bottom panel!

View the use of this graphic in its context
here.
Another way to simulate lasers in Pov-Ray is to create a beam of bright light and pass it through a
media that scatters or reflects some of the light (but has no emission of its own). A cylindrical
light-source could be used, but here we set-up an apparatus to collimate a point light source of
high intensity: the light was inside a hollowed cylinder with an aperture cut into one end. In the
example below, the beam has been refracted by the convex lens onto a screen:
The original context of this graphic can be viewed on our Waves page.