Combining a third beam

rhd · Jul 19, 2014

upaa27 said:
I was under the impression that somehow you would change the wavelength to one of the beams to 470.

(...)

Is there anyway to change the wavelength to 470?

Sort of.

When you're buying the diode from DTR, you click the button labelled NDB7675 or the button labelled M462 ;p

upaa27 · Jul 19, 2014

IsaacT said:
You would need to use a 470nm diode to begin with. You can't just change a wavelength.

Ok thanks for clearing that up.

ARG said:
There's going to be a lot more loss than that. Count your bounce mirrors too, and a wave plate if you're using one.

I highly recommend stanwax's cubes. The efficiency I got with one of them was near 100%.

I will look into those. The one I have been using at the moment is Thorlabs - PBS101 10 mm Polarizing Beamsplitter Cube, 420 - 680 nm mainly for testing as it has a very wide transmission range.

upaa27 · Jul 19, 2014

rhd said:
Sort of.

When you're buying the diode from DTR, you click the button labelled NDB7675 or the button labelled M462 ;p

Lol those diodes are pretty new so I think I am going to wait for more reviews for it :crackup: Also the efficiency looks really bad when provided over the standard current.

upaa27 · Jul 19, 2014

CDBEAM777 said:
MMmmmmm ? What you really want are three (3) NDB7A75's. Just knife edge em !!

See TRIDENTIS BUILD-Three (3) 445 Combiner-Knife edge

http://laserpointerforums.com/f65/tridentis-6-7w-blue-beauty-83781.html

Yes....the beam to beam to beam alignment, at several miles out, will not be perfect. But then, the beam to beam to beam alignment on any method of optics combination will have some alignment issues, at great distances ! That is just the way it is.

I predict that with the divergence of the NBD7A75, you will need a form of corrective optics. Maybe Anamorphic prism's or a set of Cylinderical lenses.

I think you may need the correction factor of the Cylinderical lenses vs the Anamorphics. Not sure as I have not yet experimented with a NBD7A75.

The Tridentis has Anamorphics after the knife edge arrangement. But the LD's are the 9mm variant, not the NBD7A75. I have a concern about all three (3) beams passing thru the Cylindericals, for really, only one beam will be dead center of the Cylindericals and the other two ,ever so slightly off the center axis.

I have yet to experiment with this so you may be limited to an Anamorphic Prism pair. The down side to this is about 3~4% more power loss with the Anamorphics. There is that pesky optical trade off again !

Good luck !

Haha more powah! :lasergun:

That is a really nice build! Only question is... can it light a match?

ARG · Jul 19, 2014

upaa27 said:
Ok thanks for clearing that up.

I will look into those. The one I have been using at the moment is Thorlabs - PBS101 10 mm Polarizing Beamsplitter Cube, 420 - 680 nm mainly for testing as it has a very wide transmission range.

Whoa. That's pricey

You would be best off using one that's not broadband, one that's made specifically for the blue spectrum. Same with the bounce mirrors, don't use broadband.

upaa27 · Jul 19, 2014

ARG said:
Whoa. That's pricey

You would be best off using one that's not broadband, one that's made specifically for the blue spectrum. Same with the bounce mirrors, don't use broadband.

Yeah found that out the hard way... XD

My latest idea is to pbs a NDB7A75 and a NDB7875 together and it pass through a dichro with an m426. This might be a bit difficult though...

EDIT: The m426s seem to be having the EXACT same wavelength readings as the 9mms. I am a bit confused here as it is listed at 462.

rhd · Jul 19, 2014

upaa27 said:
My latest idea is to pbs a NDB7A75 and a NDB7875 together and it pass through a dichro with an m426. This might be a bit difficult though...

That doesn't make any sense. If you're going to spend $150 on an M462, and another $75 ish (?) on a dichro and some sort of tiny mount, that's $225 that you could just use to upgrade the NDB7875 in your setup to a second NDB7A75, and save complexity by using just 2 diodes instead of 3 (likely with better results).

upaa27 said:
EDIT: The m426s seem to be having the EXACT same wavelength readings as the 9mms. I am a bit confused here as it is listed at 462.

It would be a good idea to take a bit more care in the part numbers you're talking about. This thread is full of a lot of sloppy mistakes that probably cause half the confusion that has come up so far.

Presumably you're talking about M462s. What are you comparing them to that causes you to think they're mislabeled / mis-advertised / mis-whatever? If you're going to point out what you think is a mistake / confusion / error, it would be a good idea to provide us with more detail to evaluate your question / claim. What 9mms are you talking about? We have 9mm diodes that range anywhere from about 440nm to 475nm, spanning a bunch of part numbers, and heck, we even have 9mm 520s. What diodes are you talking about?

It's fine to be confused, but don't make us do the work of organizing your question when we're just trying to help

At least lead us to the source of your confusion.

upaa27 · Jul 19, 2014

rhd said:
Presumably you're talking about M462s. What are you comparing them to that causes you to think they're mislabeled / mis-advertised / mis-whatever? If you're going to point out what you think is a mistake / confusion / error, it would be a good idea to provide us with more detail to evaluate your question / claim. What 9mms are you talking about? We have 9mm diodes that range anywhere from about 440nm to 475nm, spanning a bunch of part numbers, and heck, we even have 9mm 520s. What diodes are you talking about?

It's fine to be confused, but don't make us do the work of organizing your question when we're just trying to help At least lead us to the source of your confusion.

Sorry about the confusion http://laserpointerforums.com/f40/2w-m462-462nm-laser-diode-90132-2.html scroll down to the post where you spectroed it and read the whole thing. The 9mm I am talking about is the NDB7875. Again, sorry about the confusion guess I am just going on a rant and forgeting to back up my points. :yabbem:

rhd · Jul 19, 2014

upaa27 said:
Sorry about the confusion http://laserpointerforums.com/f40/2w-m462-462nm-laser-diode-90132-2.html scroll down to the post where you spectroed it and read the whole thing. The 9mm I am talking about is the NDB7875. Again, sorry about the confusion guess I am just going on a rant and forgeting to back up my points. :yabbem:

The NDB7875 does not have the same wavelength curve as the M462. The NDB7675 does (or at least seems to from the very limited initial testing we've done).

upaa27 · Jul 19, 2014

rhd said:
The NDB7875 does not have the same wavelength curve as the M462. The NDB7675 does (or at least seems to from the very limited initial testing we've done).

Ok thanks for the info. For just using 2 ndb7a75s it would cost about $600 and to use the 1 ndb7a75, 1 ndb78 and 1 m462 and Optical Filter DICHROIC460DRLP 25x36 Beamsplitter 45 Dapi Fitc Separator | eBay it would cost about $555 NOT including all the drivers, modules and lenses. So yeah I might just go with 2 ndb7as as it will be cheaper. Also, the dicro you listed looks like it has the transmission cutoff at around 425nm. So it would not be optimal to use any 445 nm diodes as I will loose about 17% power due to it being on the transmission curve and reflectivity. Is this correct?

Just trying to clear up some points with you guys. I need to sleep more often :crackup:

Combining a third beam

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