New Nichia 9mm 1W 520nm diode (NDG7475T)

Re: New Nichia 9mm 1W 520nm diode

Makes sense. Is that why the blue 9mm diodes get cropped with the 3 element glass lens and cast a much uglier beam with the G lens?

Re: New Nichia 9mm 1W 520nm diode

I was browsing eBay n ended up on techhoods page and seen these for $999, and was just about to post on here n see if techhood had a typo lol, then I googled nichia 1w 520nm and found this thread. Jeesh, I gotta stay off the net or IMA go broke....

Re: New Nichia 9mm 1W 520nm diode

I'll admit I've been searching feebay every couple days waiting for this (or any high power green) diode to pop up

Re: New Nichia 9mm 1W 520nm diode

Atomicrox said:

It was my understanding that the angle doesn't matter as long as the fast and slow axes have similar angles. That way a regular lens can collimate the beam. If they're different the beam will be more line-like. Am I wrong?

Click to expand...

Noooo!, the angles can always be changed; what cannot be changed is the emitter which dictates everything!!

Re: New Nichia 9mm 1W 520nm diode

The datasheet divergence means nothing, then?

Re: New Nichia 9mm 1W 520nm diode

Wat.

Unless corrected, those angles are the basis for the spot size at a distance. The bigger the angles AND the bigger the difference in the angles, the more the spot is a line.

Re: New Nichia 9mm 1W 520nm diode

Atomicrox said:

Makes sense. Is that why the blue 9mm diodes get cropped with the 3 element glass lens and cast a much uglier beam with the G lens?

Click to expand...

Yeah, pretty much.
The G lenses have a very short focal length and a high numerical aperture (0.6) according to some old specs that came up when we first started using them so they collect more light. The disadvantage is that the close focus distance means the divergence with the G lens is large.
I don't know the specs of the 3-element lenses but they don't get as close to the diode as the G lenses so some of the beam gets cut off and that is where most of the power loss comes from. This "cropping" effect and the longer focal length is what makes the divergence a little better.

If I had the money to invest, it would be a good idea to develop a larger diameter lens like the G lenses for these multimode diodes.
A large diameter (perhaps 10mm aperture) single element lens would not only collect all of the light from these multimode diodes like the G lenses do but also would be able to provide much better divergence. For comparison the aperture of the standard aixiz and G lenses is only like 4-5mm.

The only sacrifices would be the larger beam diameter at the aperture and some convenience... a larger module would have to be developed for the larger optics. Used with single mode diodes like the LPC reds, the new 520s, or 12x 405s, you can expect really low divergence.

Re: New Nichia 9mm 1W 520nm diode

Interesting, what do you figure would be the ideal raw divergence? Too low might need too much focal distance, too high may crop the beam.

Re: New Nichia 9mm 1W 520nm diode

Lenses only bring the angles into focus. The line is a focus of the emitter shape, corrective optics make that line more into a circle by compressing it.

Divergence grows with emitter widths.

Turning a raw diode beam into a spot is collimation of the angles, when doing this the source beam expands in the near field and decreases in the far field. All diodes can be colimated but the beam will be huge if the initial divergence is also quite large.

So when making a laser for shows the source need to have low initial divergence in order to colimate it and still have a beam that fits on Laser scanner mirrors which ideally means < 3mm

For Laser pointers this does not matter because it is not required to have a <3mm beam.

All diodes can be used / colimated but the trade of is beam diameter.

RA_Pierce: you don't need to have a special lens produced; you can buy larger lenses already and make a broader 3 element colimator but that is a trade off when you can do it with prisms.

"
I don't know the specs of the 3-element lenses but they don't get as close to the diode as the G lenses so some of the beam gets cut off and that is where most of the power loss comes from. This "cropping" effect and the longer focal length is what makes the divergence a little better."

The reason for the cut off is not due to distance from the diode, it is that the divergence has been lowered which results in a larger beam inside the 3 eliment lens, you are actually cutting off the real size of the beam.

I did a lot of research into diode colimation and have a huge test stck of lenses numbering around 3,000: so when I start to try a diode I can find pretty quick the right lens combination for a desired target beam.

Re: New Nichia 9mm 1W 520nm diode

andyf97 said:

All diodes can be colimated but the beam will be huge if the initial divergence is also quite large.

So when making a laser for shows the source need to have low initial divergence in order to colimate it and still have a beam that fits on Laser scanner mirrors which ideally means < 3mm

For Laser pointers this does not matter because it is not required to have a <3mm beam.

All diodes can be used / colimated but the trade of is beam diameter.

Click to expand...

Yes, but the beam can always be shrunk down using additional optics, no?

Re: New Nichia 9mm 1W 520nm diode

andyf97 said:

RA_Pierce: you don't need to have a special lens produced; you can buy larger lenses already and make a broader 3 element colimator but that is a trade off when you can do it with prisms.

Click to expand...

Yes, beam correction optics like cylindrical lenses and anamorphic prisms will improve the beam profile.
But these are not practical for handheld lasers which is what this forum is primarily about. Also, correcting the beam is not my concern with this idea.
I'm not sure what you mean by the thing about the 3 element collimator.

3 element optics introduce more surfaces to reflect light and more glass to absorb it. That's what I want to avoid. What I am talking about is using a single element optic like the G lenses but larger diameter and with a longer focal length. The beam profile will still be a line but the divergence would be much lower. I think it would be an ideal single element solution to the ugly beam problem we have with these high power diodes.
At the moment our most convenient options are the G-lenses which have lower losses but terrible divergence (with multimode diodes) and the 3-element lenses which have horrible losses but lower divergence.
A larger lens would get us better divergence AND lower losses. The sacrifice would be the beam diameter at the aperture would be large but I can live with that.

I have a bunch of 16mm lenses that I used for 808nm C-mount diodes. The beam quality was much worse than the multimode 445s but with these lenses I was still able to get decent divergence without wasting a bunch of light.

Re: New Nichia 9mm 1W 520nm diode

Yeah, the beam profile on some of the IR diodes is very divergent. They make the M140 look like almost
nothing. I've seen more than one with a die you can measure with a ruler. The ones used for pumping
are often this way for obvious reasons, one or another.

Re: New Nichia 9mm 1W 520nm diode

The Lightning Stalker said:

Yes, but the beam can always be shrunk down using additional optics, no?

Click to expand...

You can shrink a beam indeed but he divergence will go up.

Re: New Nichia 9mm 1W 520nm diode

andyf97 said:

You can shrink a beam indeed but he divergence will go up.

Click to expand...

Now IM confused. I though divergence can be set by collimation optics? And that the beam will just be bigger...

Someone halp me

:beer:
-Matthew

Re: New Nichia 9mm 1W 520nm diode

Do the specs show the beam distribution plot?

Re: New Nichia 9mm 1W 520nm diode

KRNAZNBOY said:

Now IM confused. I though divergence can be set by collimation optics? And that the beam will just be bigger...

Click to expand...

Divergence ~ 1 / Size_beam
Thus smaller beam = larger divergence. Like with w shorter focal length lens.
Bigger beam = smaller divergence. Like with a longer focal length lens.
Of course optics should be aligned appropriately.