Magenta laser build

[julianthedragon]

What would be the best technique for combining a single mode 635nm diode and a single mode 405nm diode to create a magenta or pink beam in a handheld host (or stationary but handheld preferred)? Other wavelengths can work but these two seem to be easy to find in single mode in the <100s of mW.

If one were to find these diodes such that they produced beams with similar specs and they were focused to infinity, is there a setup that would create a perfect pink laser beam with virtually no error (no leaking red or violet due to slight differences in the beams), no matter how close or far from the beam/aperture?

Not looking for RGB lasers, just thinking about a dedicated magenta

 

[julianthedragon]

Update- I found this thread which gets into some interesting details about combining wavelengths and shows some previous attempts, but my qs about the beam specs and beam combining techniques still hold

Combine red and violet diodes

I wanted make a pink laser without combine diodes. I searched for a wavelength of the pink colour and i noticed it not even exist! So if want make a pink laser i assume you must combine blue diode and a bit more powerful red diode... But here it comes a question, what will be the result of...

laserpointerforums.com

 

[CurtisOliver]

For perfection both lasers would have to have totally equal beam specs and be perfectly aligned. The chances of two laser diodes having the same divergence and same beam roundness and diameter is very slim. It will be a balance between spot size and divergence to get it right. To reduce divergence you increase spot size. Dichroics would perfectly overlap the two lasers.

 

[julianthedragon]

The chances of two laser diodes having the same divergence and same beam roundness and diameter is very slim.

If I understand correctly, divergence is not only about corrective optics but also an inherent divergence of the laser diode itself? Is it possible at all for the two diodes at opposite ends of the spectrum to be similar in divergence right out of the diode or is it going to take experimenting with lots of different lens setups?

I understand that regardless to find two diodes that similar it would require sorting through a bunch of different possibilities, maybe starting by comparing data sheets and then ordering a few of the promising ones and comparing them in person.

OPSL lasers cross my mind since I have read they have DPSS-like beam specs but use a semiconductor like a solid state diode (I don’t know much about these so correct me if I’m wrong).

To reduce divergence you increase spot size. Dichroics would perfectly overlap the two lasers.

Thanks. I’ll look into how dichroics work and how to orient them. Reducing divergence would probably make the job of matching beam size over the length of the beam easier

 

[Sowee7]

If I understand correctly, divergence is not only about corrective optics but also an inherent divergence of the laser diode itself? Is it possible at all for the two diodes at opposite ends of the spectrum to be similar in divergence right out of the diode or is it going to take experimenting with lots of different lens setups?

I understand that regardless to find two diodes that similar it would require sorting through a bunch of different possibilities, maybe starting by comparing data sheets and then ordering a few of the promising ones and comparing them in person.

OPSL lasers cross my mind since I have read they have DPSS-like beam specs but use a semiconductor like a solid state diode (I don’t know much about these so correct me if I’m wrong).


Thanks. I’ll look into how dichroics work and how to orient them. Reducing divergence would probably make the job of matching beam size over the length of the beam easier

OPSL lasers are interesting, they use a semiconductor laser medium, usually optically pumped by a laser diode that (usually) gets frequency doubled inside the cavity by a nonlinear crystal

 

[julianthedragon]

New idea: what if you used an invisible UV diode whose beam was always larger than the red diode but combined to make magenta? So the overlapping part is invisible and the whole area of visible light is pink

 

[julianthedragon]

OPSL lasers are interesting, they use a semiconductor laser medium, usually optically pumped by a laser diode that (usually) gets frequency doubled inside the cavity by a nonlinear crystal

So the output wavelength will be half the lasing wavelength of the semiconductor? Or am I oversimplifying? Is the process inside the cavity what gives it its DPSS-like beam specs?

 

[Deleted member 17304]

Invisible uv is invisible, it wouldn't have any visible effect on red when mixed...

That said, even 375nm is barely visible. Our eyes can't focus on it, so it would probably appear as a dim violet halo around the red dot if the beams overlapped.

 

[thanhtung]

Here is my DIY Magenta and white Laser:

 

[icecruncher]

Update- I found this thread which gets into some interesting details about combining wavelengths and shows some previous attempts, but my qs about the beam specs and beam combining techniques still hold

Combine red and violet diodes

I wanted make a pink laser without combine diodes. I searched for a wavelength of the pink colour and i noticed it not even exist! So if want make a pink laser i assume you must combine blue diode and a bit more powerful red diode... But here it comes a question, what will be the result of...

laserpointerforums.com

You will have the best chance with single mode diodes (vs multimode). what you are asking for is basically what a decent quality projector is doing with 3 diodes (or more). You will never get perfection, but you can get a very good beam that will stay true to color for the range of your vision, not perfect but close enough.

Either requires dichros or a PBS cube

Also very hard to do in a handheld, much easier in a lab setup with at least one bounce mirror, but still not easy.