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FrozenGate by Avery

High power single mode

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jonasq

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Hi guys,

I am new to this forum, so I hope this does not break any rules.

I am trying to build a high power (some Ws) white light (blue+green+red) laser source which is single mode (spatial). Ideally I would just want to buy e.g. 1W diodes for 450nm, 550nm and 650nm and couple them to their respective single mode fibers. Such diodes, if existent, are extremely expensive (see Thorlabs) which is why I want to use several single mode diodes at each wavelength.

The question is: which combination of diodes can I buy that offer the most power/money but are still single mode.

I had a look at the Sticky: List of Diodes but it does not state prizes and getting a quote for each takes time. This is why I thought, maybe somebody already has experience in this! :)

Cheers,
Jonas
 





Try the following. Get a 700mw Red(any) A 1W 520nm Green, and a 2W 450-460nm Blue. Combine them as usual and then put a spatial filter on the result to trim the beam.
If you really want to do it right, make sure all the beams have the same divergence out as far as you can measure. Do the same as above.

A spatial filter is as follows. Take a lens doublet or triplet since you have all three colors. Put a piece of metal at the focus and prick it with a pin. The smaller the hole the better. Put a second same lens on the out put. The idea is to putthe pinhole just in front of the focus or just behind it. Move it around to find the best location. Move the lenses first to make the beam coming in the same as going out the nad the pinhole. This trims the trash off the beam. IF you do this right you will have a near ion perfect white beam after adjusting color balance.

Second idea. Buy one of the new yellow lasers and combine it with a blue laser. This will make a very nice white but the power is limited for now. The full rgb will give 2-3W white. the yellow blue under 100mw.
 
Multiwatt is not possible for single mode diodes (yet). What exactly are you building, and why are you insisting on these particular powers and transverse modes?
 
The lack of higher power single mode LD's is a bit frustrating indeed.

If you want to make a system with a neutral white balance the red is really limiting for that. You really need a lot of power in the red to get the proper white balance, and nothing single mode is available to complement a 1 watt green and/or blue afaik.
 
You will get more effective brightness if you use a 638nm diode for red instead of a 650nm one. You will also get more brightness using a 488nm diode instead of a 445nm one. But, using single mode diodes will also limit your output power considerably. That is why I suggested these wavelengths instead of the higher power ones as they will give you an overall brighter beam.
 
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Try the yellow blue combination. 575/460-470. I know 445/575 is amazing but paul is correct on brightness. Just not sure how far you can push the blue with yellow combo and still get white.
 
jonasq said:
Hi guys,

I am new to this forum, so I hope this does not break any rules.

I am trying to build a high power (some Ws) white light (blue+green+red) laser source which is single mode (spatial). Ideally I would just want to buy e.g. 1W diodes for 450nm, 550nm and 650nm and couple them to their respective single mode fibers. Such diodes, if existent, are extremely expensive (see Thorlabs) which is why I want to use several single mode diodes at each wavelength.

The question is: which combination of diodes can I buy that offer the most power/money but are still single mode.

I had a look at the Sticky: List of Diodes but it does not state prizes and getting a quote for each takes time. This is why I thought, maybe somebody already has experience in this! :)

Cheers,
Jonas
Click to expand...

What is your geographic location ?

You are responsible for being in compliance with your Countries laws.

Also let me take a moment and mention laser safety glasses that attenuate the wavelength you will be working with, any laser over 5mw has the potential to cause serious eye damage, so you will want to protect your eyes.
 
paul1598419 said:
You will get more effective brightness if you use a 638nm diode for red instead of a 650nm one.
Click to expand...

The brightness per mW is certainly a lot better on 638 vs 650, but the availability of single mode diodes is better on 650. I think oclaro does a 100-120 mW single mode 638, and sharp has something similar, but that's about it?

The 650-ish laser diodes from fast (24x) cd burners can be ran a lot harder, perhaps to half a watt or so with ample cooling.

While it seems like very dated technology there still are plenty of 24x dvd writers on the market, and they are cheap too ($20 for the whole drive). Note that those are NOT blu-ray and dvd combo drives, they only do dvd's (and usually cd's). The red diodes from blu ray drives are certainly usable single mode diodes, but usually are less powerful than the ones in fast writers that don't do bluray.

Prices are fairly low now since this is all old stuff no one really wants to use for the intended application anymore. They may have been sitting on a shelf for 10 years, but could still be the cheapest source of a high power single mode 650 nm diode... as long as you are able/willing to extract the diode yourself.
 
The LPC-836 and 840 can be pushed to 400 mW, but that is about it. I'm not sure how hard the single mode 638nm diodes can actually be pushed. It could be 250 mW or higher, in which case I would still go for the 638nm.
 
kecked said:
Try the yellow blue combination. 575/460-470. I know 445/575 is amazing but paul is correct on brightness. Just not sure how far you can push the blue with yellow combo and still get white.
Click to expand...

The spectra for white falls within the lines of 470 and 575, you could get by with just these two and drop red and green.

Issue is a 470 source is going to be multimode and a 575 is dpss cheese still and the beamspecs will certainly not match eachother.
 
That would certainly pose a problem when using it at any distance and you care about what the dot looks like. If it's for a beamshow or something you can get a away with it as it's far less noticeable when scanning the beam around.

Guess there are ups and down to this approach - using only 2 colors makes construction and alignment a lot easier, but can only produce yellow, blue, and anything between warm and cold white. Pushing both diodes to full power will probably result in pretty cold light, but it can still look impressive.
 
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