View Full Version : Visible Laser Pointers in CO2 Lasers

Brian Leavitt
05-02-2016, 1:33 PM
Simply out of curiosity...

Does anyone know why laser manufacturers all seem to use red laser pointers as opposed to green?

I guess I started wondering about this because I'm thinking about putting a beam combiner in my Chinese cheapie laser. I hate the head-mounted laser pointer.

Kev Williams
05-02-2016, 2:42 PM
My Triumph either didn't come with a red pointer or it's never worked, so awhile back I bought 3 pen-pointers, a red, green and blue. The green's the brightest of the bunch, and is just about too bright to focus to a nice dot. The red's almost as bright. The blue laser is useless because the yellow lens absorbs the blue light!

To make my own pointer, I laser cut a plex o-ring that fits snug around the tip of the red pointer, and almost as snug in the mirror-hole over the lens. I test-fire the laser onto a piece of scrap plastic, then press the pointer into the hole, then align the red dot to the test fire dot. Doing this takes a couple of seconds, but it works great! At first it was too bright (especially the green) so taking a cue from the laser pointer on my Gravograph IS400,, I cut a small 3/8" or so circle out of some .010" brass shim stock, and drilled a really tiny hole in it, then taped it over the end of the pointer. The light coming thru the tiny hole focuses to much smaller, easier to use dot on my table.

Anyway, I don't see why green wouldn't work?

Keith Downing
05-02-2016, 4:54 PM
Red = danger? Perhaps that's the thought process.

Dave Sheldrake
05-02-2016, 6:06 PM
Diode cost

Greens are frequency doubled IR's and tend to get hot with extended use (die basically)

The machines I have that still have aiming lasers on them have all be swapped out for green. Green at 532nm is bang in the middle of the visible optical wavelengths so will appear brighter than any other colour when in effect they may actually be weaker than one further from the midrange. 445's (blue/violet) aren't the best thing to have on a machine, the photon energy of that wavelength is pretty high and will damage eyesight far below what a red (+/- 650) will at the same power

As a *general* rule, shorter the wavelenth the more permanent the eye damage will be given the same output as the shorter wavelengths focus at the back of the eye on the optic nerve rather than by causing a laser induced cataract on the lens that is sometimes repairable