View Full Version : Mixing Red Dpss Lasers

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02-25-2008, 08:57
Hi Guys

I have a Beam combiner for mixing 2 red lasers

My question is can i use any red lasers or is there a polarity issue ?

I was once told that the laser beams need to of different polarization ?

Any ideas ?


02-25-2008, 09:43
im not sure it depends on what type of beam combiner if it need polariation the 2 lasers need to be 90deg out so just turn one on its its side :)

02-25-2008, 10:09
yes, combining any 2 laser beams (same wavelength) through a PBS cube is possible if the polarization state of the 2 beams is known. if the polarization of each beam isnt known i would assume you can just rotate one laser until the power output after the PBS reaches the combined total. how you could do that while still keeping the beams aligned through the PBS cube...well....that i have NO idea about!! :)


02-25-2008, 12:34
Are they DPSS or direct injection diodes?

02-26-2008, 08:39

They are standard red laser diode modules with a 650nm laser diode

02-26-2008, 08:56
OK, that's not DPSS. DPSS is an IR pump diode directed into crystals for frequency conversion. If your diodes are polarized you can rotate one 90 degrees from the other into a polarized beam splitter cube to combine them.

02-26-2008, 13:23
Why cant I get two dule maxuzy set ups and combine them?

02-26-2008, 13:57
Because you can only combine beams with different polarization if you use a polarizing beam splitter (PBS). When you use a PBS cube to combine two linearly polarized beams (such as those from a laser) you will get circular polarization in your exiting beam. If you try to combine two beams with circular polarization you will get two exiting beams from the PBS, because it splits the beam into components with different polarization (hence the name).

02-26-2008, 15:35
If you combine H and V pol you end up with random pol and if you combine random with random you end up with cancellation I believe..

02-26-2008, 20:47
Tocket you are right, but its not a circular pol - its random like Steve-o said. Although it doesn't result in cancelation - in the situation with the PBS you will just dump 1/2 of the randomly polarized beam out keeping the 1/2 that is correct with the polarization that the side of the cube wants.

In fact combining 2 Dual Maxyzs modules together with a PBS will result in a less powerful beam than compared to a single Dual Maxyz. Because of the loss of optics.