Beam combiners for 445nm ?

[educa]

Hi,

1) Does anyone know where I could find beam combiner (those glass-like cubes) to combine 2 445nm beams into one?

2) Also, since the 2 beams come from a module, the modules focus on their lenses, but should I then mount another lens behind the beam combiner to create the focal point again? Or should I just try to focus each diode/module individually to make sure they have same focal point just AFTER the beam combiner?

3) I am used to work with 800+nm spectra labs modules which a re fibre coupled, but I want to move away to visible laser because I'm not that happy with invisible stuff If you look though a 445nm protective goggle then it should filter out the dangerous energies, but if I point the laser beam to a piece of wood or so (which will start burning a little) will I see the SPOT on the wood through the glasses or will that also be completely filtered?

If its going to be filtered, then I'd better combine the beam also with a very cheam <5mW red dot laser so I can at least see where I am aiming to.
The purpose of my laser is by the way to mount onto a cnc machines machining head, not for a laserpointer.

Kind regards,

Bart

 

[Bluefan]

What you are searching for is called a Polarising Beam splitter (PBS). It's splits a beam into it's two different polarisations, but the reverse is also possible: to combine two beams of different polatisation.

You can collimate both beams (focus at infinity) as you normally do, the combining of the beams won't change this.

Most materials will have some flourescence that will be visible after the goggles, Usually it isn't needed to have goggles with an OD of less than 6.

 

[educa]

Hi and thanks for reply.

So if I understand right, when using such a PBS, I would have to set both modules to focus on infinity (so a parallel beam like real lasers should be according to most people) and then they pass through the PBS, but now there is something I don't understand.

Since the PBS needs 2 lightsources with differend polarisation, should I use some kind of polarising filters too? Or is no filter needed because thats all built in into the PBS and you just point 1 pointer to 1 side and 1 to a side 90° difference ?

Any idea where to get such PBS ?

PS. I'm from Belgium, so bedankt voor je bericht

 

[Bluefan]

Most lasers are already polarised by themselves and diode lasers are certainly. The PBS can combine one horizontally polarized laser with a laser with a vertically polarized laser. Changing the polarisation of a laser is done the easiest by rotating it around the optical axis.
I don't know a place to get such a PBS except professional optics manufactors like thorlabs:
Thorlabs.com - Polarizing Beamsplitter Cubes
But it should be possible to find them cheaper.

P.S. Graag gedaan

 

[clif]

Don't Blu-ray sleds have little PBS cubes in them? Might be too small to work with a 445nm laser diode though...

 

[LaserAdct]

Don't Blu-ray sleds have little PBS cubes in them? Might be too small to work with a 445nm laser diode though...

They do, but as you speculated they are extremely small and it would be a real challenge/hazzle getting something usefull out of them. I have tried, but gave up and bought two 15mm ones from a member here on LPF that had a sale going

 

[offroadfreak8582]

Could this be a way how wannaburn got his 3.5W dual ld laser? And if i understand correct you have to focus the beam to infinity before the beam hits the pbs cube? Is it possible to place the diodes very near to the pbs cubes and focus the beams afterwards?

Greetings,,

 

[Tech_Junkie]

Could this be a way how wannaburn got his 3.5W dual ld laser?

Exactly. Looks like he was using a sled too.

 

[offroadfreak8582]

Exactly. Looks like he was using a sled too.

How hard would it be to allign and machine everything? Kinda want to try this myself.. too bad i don't own the proper machinery:gun:

greetings,,

 

[Tech_Junkie]

You'd need a lathe and a mill if you want to do a handheld.

You could easily do a ghetto lab style with simple tools. Well, its still tough, but doable.

 

[mattco2]

You'd need a lathe and a mill if you want to do a handheld.

You could easily do a ghetto lab style with simple tools. Well, its still tough, but doable.

Hot glue and duct tape make for a very "interesting" labby no doubt but in all seriousness combining 2 beams is no joke it can be very hard getting the optics lined up and getting a single dot you also will have losses in the optics so don't expect to have three watts come out of 2 1.5 watt lasers.