YAG and CO₂ lasers typically have to be focused very tightly on metal in order to cut. Typically, they use a glass or Sapphire cone-type lens to get a very fine spot with the greatest energy per area².

Anytime you have a laser beam, no matter how much you culminate it, it's going to spread. Maybe not as much as the beam of a flashlight, but it will spread; thus reducing the energy density at the work surface. I've had some experience using fiber with burning lasers, and after the beam leaves the fiber it begins to spread out. Cutting in these instances occurs within only about a few mm from the fiber. Any further than that and the energy density falls off rapidly.

If you can imagine that a typical YAG rod is about 8mm thick, you're going to get an 8mm beam unless you focus it down. You could use spatial filtering (a small hole in a metal disk), but, again, you're using only a small part of the beam and it's energy.

I have a culminating lens that can hold a normal sized beam for about 10 miles, but within that 10 miles the YAG beam has a rather large diameter - about 8mm (again). If hooked to, say, a 5000 Watt YAG laser, it could do some damage at a distance, but it is incapable of cutting fine patterns in anything. It's far better for setting fire to 2" X 4"s.

So, what type of terrorist activity are you interested in?

Thanks for the response,

but I think you misunderstood me :). By fiber laser I mean the actual fiber laser, in which the fiber itself is the laser resonator, not YAG laser with fiber for beam assistance. The divergence in fiber laser is less than in fiber assisted YAG laser and the beam quality is much better.

This is kind of a laser system I was thinking.

http://www.laserfocusworld.com/display_article/355828/12/none/none/INDUS/5-kW-single-mode-fiber-laser-is-cutting-edge-in-more-ways-than-on

A very intresting development in lasers! Just one thing, what's the price tag?

hello sir , hans laser technology co, ltd , mumbai ---

chandrashekhar karni --- 09320060599 .

call me on my number regarding ur application

It is possible to collimate a beam from a fiber laser and steer it with a galvo driven mirror to cut shapes in very thin material.

A normal laser cutting process melts and vaporizes material and then pushes it out of the bottom of the cut with assist gas. With remote cutting you need to vaporize all the material. Material that is simply melted recasts in the kerf of the cut. Since a single pass vaporizes away only a little material several passes are often required to cut material that is only a few thousandths of an inch thick. Forget something like 16 gage for now.

Some of the best research in remote cutting has been done by the Fraunhofer Institute in Germany. http://www.fraunhofer.de/EN/institutes/alliances/Surface_Technology_and_Photonics.jsp

The maker of high powered fiber lasers is IPG Photonics. http://www.ipgphotonics.com/apps_mat_lab_cutting.htm

We make high speed production laser cutters for metals but are not remote cutting.

Rick Neff

Cincinnati Incorporated www.e-ci.com