Got Red?

[wes]

Back to the other topic- Interesting pic on the German section of Laserfreak- I just loves them groovy mirror mounts

o.k,so it looks like he's pairing beams side by side,then into the cube,correct?
yeah, i had a hard time seeing it at first but he'd have to to be able to use the same wavelength for all the diodes.
fat beam but good specs aside from that,right?

i may have missed it, but does anyone here have experience with combining two different wavelengths of red,and if so,what is the resulting color like?
pics?

[steve-o]

A prizm will deflect different wavelengths at different angles of incidence.
Wonder if one could be used as a combiner instead of a splitter?

[steve-o]

Does anybody know if these red 650s from aixiz are any good? MTTF?

[buffo]

A prizm will deflect different wavelengths at different angles of incidence.
Wonder if one could be used as a combiner instead of a splitter?

Yes, you can use a prizm in place of a dichro. However, it's a lot more difficult to align, and in general you'd need more space inside the projector to get the beams spaced properly. (The geometry lends itself to a long, narrow layout.) But it will work.

Note that this doesn't change anything though. It's acting just like a dichro, which means it's wavelength specific. You can't use it to combine two beams of the same frequency, but you can use it to combine two different frequencies, just as you would with a dichro.

Adam

[lucerne]

Does anybody know if these red 650s from aixiz are any good? MTTF?

They are not 650nm... normal 658nm.

You can have a look for yourself at ebay. Just check the image of the datasheet.


greetz

[steve-o]

Well them lying b*stards..
____________________________

Adam - can you find a dichro that separates 650 and 660 , I havent had much luck..

[Lampy]

I just made a quick phone call to Lee Filters (who make gel and dichroics for lighting and photography) and they said they wouldn't be able to make a custom dichroic in those wavelengths. They couldn't say why but could it be that you can only choose one wave length at a time, ie if you choose to reflect 660nm the laws of physics decide what is transmitted?

[Lampy]

Looks like the prism method might be the way to go.

[buffo]

A dichro that would reflect 660 and pass 650 would be hard to make. That's not much tolerance to work with. (just 10 nm) I'm sure it's possible, but it would probably be prohibitively expensive for our hobbyist application.

As for the guy from Lee Filters that said it's "impossible", I say that he's just not up to the task and doesn't want to admit it. Especially if he's normally used to making gels for lamps. They don't have the selectivity that a dichro does. A company that specializes in laser optics would be a better choice, though that will also increase the cost...

But it's clearly possible; there's nothing in the laws of physics that would prevent you from building a dichro that reflected 660 nm and passed 658 nm... But it would be *damn* hard to make - and expensive. Consider too that there are laser optics available on the market today that will kill certain lines by allowing them to pass through while reflecting other lines that are *very* close so they will be amplified in the cavity. So yeah, it's doable... But you already know how expensive laser optics are!

However, a dichro that would reflect 660 and pass 635 should be fairly easy to make. I've seen dichro's with less than 20 nm between their maximum reflectance and maximum transmission wavelengths, so 25 nm ought to be no sweat. Only problem is that the dichro's I'm referring to were spec'd to work in the blue-green spectrum; they wouldn't work for this red application. You'd need to find (or special order) a dichro with the correct coatings.

hmmm... Maybe I ought to make a few phone calls. I'm starting to wonder just how much such a dichro would cost. (Probably have to order a lot of at least a hundred though.)

Adam

[QUAZAR]

Can Bridge supply such an optic?