Which beamsplitter optics to use?

[VaThInK]

I'm thinking of making a 400mW+ 660nm red module by combining 2x 200mW+ 660nm laser beam together. Now, since I'm new to beamsplitter optics, could anyone please recommend what kind of optics are needed to achieve my goal? I seriously know nothing in this area. :mecry:

Now my second question is, anyone know the electronics principle behind TTL or analogue modulation in laser module driver? How does it works? Any example schematics? I'm planning on building one of this as well to drive the red above. :thinking:

Any inputs are much appreciated.

Thanks guys.

 

[Aseras]

you need a polarizng beamsplitter, so that it won't reflect one of the beams, but combines both to a single one.

a normal beamsplitter will reflect one wavelength and transmit another.

 

[yuip]

Edit: Eeek, Aseras beat me to it.

 

[VaThInK]

Thanks Aseras for helping me out. I'm not sure what is meant by polarization in laser beams or lenses but I'm assuming these beamsplitters won't work, correct? Here's the link: eBay link. Does the seller have the right beamsplitter suitable for my intended purpose by any chance? Thanks. :thumbsup:

I have a feeling that those dichroic beamsplitters on that link are only suitable to join/split beam with different wavelength.

 

[yuip]

Yep, I believe those beamsplitters will only combine two different wavelengths.

The only person I can remember selling them for a decent price is Marconi at Photon Lexicon. I think he charges $165 for just the beam splitter. He also sells dual 225mW setups for about $600. Sorry to sound like I'm plugging him, but I'm not. I've never bought anything from him, but from what I've heard his stuff is top notch.

 

[VaThInK]

WOW, that's quite a lot of cash for just a tiny lens :huh: :thumbsdow. I guess my dream of combining 2 red laser beams together is over now :mecry:. By the way, does anyone know what's the actual name of the lens that I should look for?

Thanks :thumbsup:.

 

[yuip]

Yeah, it is a good bit of money. andy_con has been looking for one and I believe a dealer chimed in over at Photon Lexicon saying he had some at $30, but the shipping is DHL or FedEx, which is about $50. I think Andy asked the guy if he could ship standard post, but I don't think he has posted a price yet.

If he can get the polarizing beam splitter for $30, I will definitely be down for one. Unfortunately it doesn't llok like that's going to happen.

Anyway, as for a specific details on a name/description, I would call it a polarizing beam splitter cube with AR coatings at 633nm/650nm. They'll look something like this picture.

Hope that helps.

 

[monkeyboy]

A dichroic mirror (or dichroic beam splitter) relfects light of one wavelength (usually at 45 degrees) and transmits light of another.

A polarising beam splitter (PBS) reflects light of one polarisation at a maximum while transmitting light of polarisation at 90 degrees to this. The PBS will work for combining your laser beams so long they are polarised (which they should be) and the polarisation is in the right direction. You can rotate the polarisation of the lasers simply by rotating the laser or by using a half wave plate.

If you consider the light loss with a cheap PBS and half wave plates, it might not even be worth doing.

 

[VaThInK]

Thanks for the info guys. So the optics I'm looking for is called polarized beam splitter or PBS. I did a little search on Google and all of the optics shops that I've come across asks big $$$ for this type of optics :thumbsdow. Pity me.

yuip: Yeah, if anyone sell this kind of optics for around $30, I'm gonna grab a couple my self for sure.