20mw 635nm diodes for 17-20$?

[ndrew2505]

would anyone be interested in 20mw 635nm diodes for 17-20$? ive been communicating with a new suplier and may be carrying these in the shop soon if enough people are interested.

edit: forgot to mention these are in a 5.6mm package

 

[scopeguy20]

Yes! These are worthwhile, imho Thanks!

 

[ndrew2505]

i think they would be worth carrying. i was asking them if they had any stronger 635s but that seems to be the highest they make/carry. they also had some 250mw 405 diodes but theyre kinda pricey with a MOQ of 500pcs...

 

[Mohrenberg]

well, if it's manufacturer rated 20mW CW, then we could probably drive them at 50mW then correct?

 

[Elektrotechniker]

well, if it's manufacturer rated 20mW CW, then we could probably drive them at 50mW then correct?

>

really?

 

[anselm]

Again:
As you push laser diodes, the wavelength increases with current and heat.
This kinda defeats the point of having a shorter wavelength red.
Don't push 635nm diodes like you would do with a 660nm or 445nm.

That being said, this seems like a good deal.
DJNY did a groupbuy some time ago, 20$ for a 20mW 635nm diode.

 

[icecruncher]

Even if you can push it to 50mw and keep it at 635, you are paying over twice as much as compared to a LOC for less brightness and less power.

I can't see it unless the power goes over 100mw and the price is reasonable, personally.

I could see spending a chunk on the 170mw version because you can exceed the brightness of the LOC and have something to show for the money. But for this level of power I don't see the point. You have a different wavelength, but that's about it, imho.

I'll wait for the big ones.

 

[seoguy]

Yep, would be interested!

As you push laser diodes, the wavelength increases with current and heat.

Hmmm...TEC, perhaps?

Speaking of which, if these guys do 635nm @room temp, wonder what wavelength we might get with some serious cooling?

I could see spending a chunk on the 170mw version because you can exceed the brightness of the LOC

icecruncher, just saw your comment after I posted mine. Not sure how high you are pushing your LOC's. But you need to remember that, due to the increased visual sensitivity to 635nm, combined with the increase in Rayleigh scattering caused by the shorter wavelength, a 635nm laser beam is going to appear approx. 4.164729x brighter than 660nm at the same output power.

So a 50mw 635nm laser beam is actually going to appear slightly brighter than a 200mw 660nm! It also looks nicer than the more common red laser color.

 

[ndrew2505]

"at -30C they emit at 646 nm"

"If I recall, it is in the order 0.3nm/C so could be around 642nm @ -35c."

quotes from PL referring to cooling 650nm diodes so cooling over driven 635s will keep them at 635 or lower depending on how much you cool them.

 

[seoguy]

"If I recall, it is in the order 0.3nm/C so could be around 642nm @ -35c."

They may have been referencing 660nm, as otherwise the math on that second quote doesn't seem to add-up?

Not sure if the temp-induced shift on a 635 would be the same or not, but if it is, that would result in 617nm at -35C! Break-out some dry ice (-78.5C), and assuming the shift stays the same, you're down around 602-605nm! Even colder, and...

OK, now where did I put that liquid Helium?! :thinking:

Even 617nm is starting to get rather orange, which is what got me thinking about this - I recall seeing someone here selling an experimental orange laser diode, that required extra cooling to reach that color?

But if this same shift continues unabated, you could get all the way to green just by cooling! (at that shift, even liquid nitrogen would seem to get you into lime green territory!)

I assume either this shift does not stay linear, and/or there is some other practical limitation that is preventing that? But it does make you wonder just how far down you can shift these guys!

Perhaps pullbangdead can shed some light on this?

 

[ndrew2505]

heres a link to the original thread

20 Diode Modules

he's using LOCs so yeah its probably closer to ~660nm.

 

[eexe]

Wouldn't they get wet at cold temperatures? Or some kind of malfunction could occur?

 

[ndrew2505]

TECS do/can cause condensation but you have to take that into consideration when designing the final product.

 

[jakeGT]

Yeah, that's the same spec sheet from phils group buy, same diode I presume. Would be awesome for you to keep them in stock, would be nice for people to be able to have access to an above 5mW 635nm diode easily available to them.

And I'd say even overdriven maybe 30-35mW with WL shift, unless your cooling them heavily


Alright, whose the wisenheimer who voted no?

 

[Crossfire]

Great wavelength, reasonable suggested price. It would be nice to have more than 3mW of 635nm at my disposal.

This gets a 'Yes' vote.

 

[icecruncher]

icecruncher, just saw your comment after I posted mine. Not sure how high you are pushing your LOC's. But you need to remember that, due to the increased visual sensitivity to 635nm, combined with the increase in Rayleigh scattering caused by the shorter wavelength, a 635nm laser beam is going to appear approx. 4.164729x brighter than 660nm at the same output power.

So a 50mw 635nm laser beam is actually going to appear slightly brighter than a 200mw 660nm! It also looks nicer than the more common red laser color.

Which is exactly what I was figuring. Even at 50mw my LOC is over 200mw, same brightness or more and the diode was half the price.

And I can't believe you can safely push this one to 50mw, but for me not worth it.

My hene lamp is aobut the same color, I like 632-635 better, but band for the buck, I'd go with the 170mw version, even though right now it's VERY pricey.

With that you are looking at a much brighter beam. Someone already had a thread with one they built on it.