PBS cubes

[RedCowboy]

Has anyone used any of the Chinese/ebay PBS cubes or found any highly affordable cubes that can hold up to 2 x 9W laser diodes ?

 

[kecked]

I think you might be better using dichroic as it is thin and can stay cool. That kind of power will likely burn the glue holding the prisms together.

 

[atomd]

Depends how much you spread the beam. PBS can be used to combine kW beams if they have low enough power density

 

[RedCowboy]

Both lasers are the same wavelength.
I have some PBS cubes that will take the power but they are small, like 8mm and I can get some larger cubes from live Lasersystems, I was just hoping someone had had good results with some of the cheap stuff on ebay or elsewhere.

 

[kecked]

Nope everyone I use above 5 w seems to brown out eventually like in months but still. Much worse obviously with blue diodes. Red never causes this. Green does but takes years. Can you knife edge? I also use a wave plate to rotate polarization when using a cube to overlap the beams. I then knife edge two such pairs. Never went farther than that.

so looked up high power cubes they are optically contacted. You might try two prism you carefully lap and contact. It’s not easy but it is fun. I looked and not see much explanation but basically you fit them till they bond to each other By polishing.

such Cubes are rated to 10J so I’d bet it makes sense to just buy the cheap ones and see what happens. All my stuff is ps pulsed high energy.

 

[RedCowboy]

Yes I enjoy knife edging, I've started using cut up reflectors from our favorite projectors because I was getting more loss than I expected from front surface mirrors. That said I think I may start using the professional prism mirrors.

I might try some 10x10 PBS cubes from live laser systems and see how they hold up..... also I think I will c-lens correct each beam 1st and then either PBS combine pairs to knife edge or skip the cubes and just knife edge the corrected beams.

However if I can combine 2 beams via. PBS cube then use just 1 pair of c-lenses I save a pair of c-lenses, however the cube has to deal with a much smaller beam footprint straight out of the infinity focused G2 primaries.

p.s. Yes I will be using a rotator on 1 of the beams before the cubes.

It's amazing how such a thin piece of coated glass can reflect a bank of eight or ten 5W laser diodes yet we can see through it.

 

[kecked]

Yes your right spread the power out and then telescope back down. Greta idea. I would not have considered that at diode levels but makes sense. Lens cheaper than optical contact cubes!

 

[RedCowboy]

Yes your right spread the power out and then telescope back down. Greta idea. I would not have considered that at diode levels but makes sense. Lens cheaper than optical contact cubes!

I am testing 1 of these small cubes I have with a pair of nubm0F diodes @3.5A ( doing 7W each 14W total into the cube ) w/G2 primaries and a quality rotator from OPT and so far it's working very well, my question is when you say your cubes brown out after a month, is that 3 hours a day 4 days a week .... so like 50 hours of runtime..... or how long would you estimate ?

 

[kecked]

Like 4 hrs a day full power 30 days so 120 hrs. Remember my stuff is pulsed with peak power in the kw.

 

[RedCowboy]

Ah yes, that could make a big difference, Thanks.

 

[kecked]

I killed a cube will a nitrogen laser in about a day!