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FrozenGate by Avery

500mw 445nm True Blue Diode $470 =)

FireMyLaser said:
500mW?? How much for just 50mW? :anyone:
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These are pretty rare as it is.

The big thing about these diodes is that they seem to fit the specs of a nichia diode, that is priced at almost double what that sale just was.

I doubt a 50mW would be much less than $500.

I would give it a year, they'll become more common eventually.
 





The seller was very cool and cancelled the transaction for me. Hopefully we can get some of these in the near future that are not multi-mode. I also got a peak at the company he works for and most likely the source of these used diodes.
 
yobresal said:
I guess I would be the guy who usually takes these kinds of expensive risks for the good of the forum so I don't so why things should be any different this time.
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:wave: Go Yob Go :wave:
 
I've been in communication with the seller, and after our conversation I see 2 big problems with this listing.

The diode is no doubt genuine in terms of wavelength, but I'm not so sure in terms of power. The seller has no real idea what power these diodes are rated at, he only knows that they will produce 500mW. For how long? No idea on that either. He's tested them for less than 10 hours. I'd be a bit more comfortable if I knew that the "500mW" diode I was buying would last.

Also, the missing case pin is kind of a large issue IMO. The case should be grounded to help make the diode less susceptible to ESD, but it's not possible to get them with the case pin intact. Of course whatever module the diode get's mounted in can be grounded with the same effect, but the fact that the case pin is apparently cut on all of these diodes tells me they're pulled form some kind of equipment or another.

The bottom line is price. The price is fairly good on these even if they'll only produce 250mW with a full lifetime. Also, not knowing the specs on this diode is no different than most of the diodes that hobbyists here work with normally.
 
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I don't know who to believe anymore. I will wait for someone who has solid info. Like a picture or video or schematic. Too many people are experts on a diode they've never seen.
 
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Thanks for the link by the way, I read through both pages and found the info very interesting. I can't wait to build a 445nm laser!
 
KGB_Productions said:
Hey yobresal,

You may have acted a little prematurely canceling that order. Looks like its pretty easy to make this into a pointer with only an aspheric lens. They are definitely not round beams, but they certainly aren't flashlights.


Recent batch of 455nm 500mW laser diodes made available on YKW ......
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I'd wait for a pic on that one..

Not that Dave and Aijii don't know what they're doing, they're both very experienced, it's just that when someone says something that goes against every piece of text I've found on the subject and my own personal experience I have my doubts about how good the beam actually is.. The people who write scientific texts on laser diodes and their collimation have degrees in the subject. I suspect they are also very experienced.

There's detailed information on both how to collimate and focus multimode laser diodes here including drawings, a basic techincal paper, and a pic. Here's another pic of a multimode red with FAC, which these diodes do not have. Since they don't have FAC, then some kind of fast axis correction is necessary in addition to a plano-convex or aspheric lens. Typically, the beam characteristics of multimode diodes are similar regardless of their wavelength. Just being blue shouldn't change their characteristics enough to simplify collimation.

Really, it all depends on your personal taste. I'm all about trying to get the cleanest beam possible which is why I always lean towards more advanced methods of collimation, but that might not be important to others, particularly those interested in portability. Go with your gut, that's all i can say.
 
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I think the detail missing is that "multimode" is a completely relative term. If it's not one, it's multi, and therein lies the possible confusion. It could be gain-guided with some massive width, or it would be what that one guy said on PL and be index-guided and only 7um wide. A 7um ridge laser would likely be multimode, but not nearly as bad as wider ridges, and not nearly as bad as a gain-guided diode.

Then, even beyond the diode, you get into "multimode" bars which are actually multiple emitters, which makes it even worse.

But just someone saying "multimode" could mean any of these things, especially if you get people who just hear "multimode" and really don't know the difference. It's a phrase that gets repeated a lot with relative certainty, even though it is a completely relative term.

If the guy on PL is right and it's an index-guided 7um wide laser, then it's likely not going to be too bad. A single mode laser may be 2 or 3 um wide, just for reference, so 7um isn't that much wider, relatively speaking. ETA: Also for reference, a PHR has a ~1.5um ridge width.
 
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Thanks for clearing that up a bit pullbangdead, guess the diodes aren't too terrible then. Sorry about dissuading you yobresal but when I see multimode on a mysterious ebay diode I can't help but err on the side of caution : \
 
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