2 or more CO2 Laser beams combining?

[Konstantin]

Hello everyone.
I wish to know if it is possible to combine two co2 laser beams into one to increase output of two or more tubes.
Is there an optic that can do that?

I guess the two tubes could be in 90 deg relative to each other and one firing the beam at an anti reflective coating ZnSe optic positioned 45 deg and the other beam firing at the reflective side thus combining the whole thing?
Maybe careful aligning must be done to intersect the two beams completely.

I am correct?

[LaserImage]

Originally Posted by Konstantin Hello everyone. I wish to know if it is possible to combine two co2 laser beams into one to increase output of two or more tubes. Is there an optic that can do that? I guess the two tubes could be in 90 deg relative to each other and one firing the beam at an anti reflective coating ZnSe optic positioned 45 deg and the other beam firing at the reflective side thus combining the whole thing? Maybe careful aligning must be done to intersect the two beams completely. I am correct?

I think it would be less expensive to by a single tube in a particular wattage than to buy two tubes at half the wattage. ie. I think an 80 watt is cheaper than two 40's. Could be wrong, but I'm not sure.

What is done often is the opposite of what you are talking about. I have a 100 watt epilog radius that has a second head so I can split the beam and effectively have two 50's - not quite 50 each, but close. This allows you to do twice the work at a reasonable speed. It doesn't take twice a long to do a task at 50 watts as it does to do the same task at 100, so it does increase your output by a significant margin.

Gary

[zax15uk]

Possible, yes.

How to combine two CO2 laser beams?

Is there a good reason to do this? It seems like it would end up costing more.

Zax.

[Konstantin]

I see.

Actually beam splitting is interesting also. Laserimage, how it is done? Could you please talk some specifics on this topic?
Thanks.

[ImanCarrot]

Sorry to throw this wobbly bit in, but these beamsplitters are typicaly 50/50 (ie 50 percent transmission and 50% reflectance)- that means you're only gonna get 50% power from each laser... and 50% plus 50% equals the initial power of one laser

Even using two right angled prisms cemented together in the typical beamsplitter arrangement (like two prisms glued together to make a cube) you're only gonna get 50/50 by definition... that's what a beamsplitter does, it erm... splits the beam. In actual fact you'll only get 50/50 in a perfect optical beamsplitter, in reality it'll be less that 50% due to absorbtion, diffraction and dispersion.

Sorry!

Oh also, if you're sticking a diverging or converging beam through a transmitting flat set at 45 degrees you'll get astigmatism, to correct for this you need to have a slight wedge in the beamsplitter- when I used to make interferometers I think the wedge was about 1 minute total indicated runnout, but this was at 633nm (visible) it'll be different at 10.6um (infarred).

[jdr]

I believe Synrad's 50 watt CO2 48 series lasers contain two 25 watt tubes to achieve 50 watts output.

[ImanCarrot]

Interesting! I'll have to look into that. Wonder how they combine the beams- I can't see how you would do it, unless the two beams are on different optical axes.

[KTP]

It only works if the lasers are linear polarized. The two 25 watt tubes in my Synrad laser are linear polarized and combined with a znse optic to produce a 50 watt output randomly polarized beam. I measured the output of each tube and the output of the combined beams and it only differed by a watt or so, so not a lot of loss in the optic. Basically, the optic is coated on one side to pass light that is polarized in one direction (say horizontal) and coated on the other side to reflect light polarized in the other direction. So one laser beam passes straight through the optic and the other one hits it on the other side via a turning mirror and is totally reflected and follows the same path as the first laser.

tube 1 -----------\
|
tube 2 -----------\--------output beam

[ImanCarrot]

Well! I learn something every day!

Many thanks for the info. Didn't know that.

[LaserImage]

Originally Posted by Konstantin I see. Actually beam splitting is interesting also. Laserimage, how it is done? Could you please talk some specifics on this topic? Thanks.

I don't have the knowledge to talk specifics. All I know is that there is a lens on the first head, closest to the tube, that splits the beam. Half goes to the first head and half to the second. I don't know how much you might lose in the process, I am just starting to rebuild the laser and haven't done any testing with it yet.