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My Eyes Deceived Me

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Well all, I've got to come clean - I was wrong about the wavelength of one of my lasers.

Although I work with 488nm light all the time, I suppose my eyes aren't all I thought they were, as I just measured the wavelength of my "488nm" laser, and it's outputting at 495nm.

Don't get me wrong, I'm happy I have the laser, it's a beautiful color and I like it a lot, but I still do really want a "true" 488 (or at least something closer). I ordered this particular Sharp diode from DTR, and I know it's not always especially certain what wavelength the diode is going to be producing.

My question for those with experience with the Sharp GH04850B2G/experience in general is this: are "in-spec" diodes common enough that I should order another one from DTR and have decent odds that it'll be closer to true 488, or should I take my lumps and move onto another project, and maybe buy a pre-validated 488 if one becomes available?

Cheers!
 



RedCowboy

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I have several 488's and they are all different, that's one thing that's really cool about them and how our brain perceives color is also not constant, try looking at the bean of your bluest 488 then turn on a 450nm next to it, the 488 will turn from blue to green instantly.....well your brain will see it differently than it did a moment before.
 
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I have several 488's and they are all different, that's one thing that's really cool about them and how our brain perceives color is also not constant, try looking at the bean of your bluest 488 then turn on a 450nm next to it, the 488 will turn from blue to green instantly.....well your brain will see it differently than it did a moment before.
Yes I've noticed that! That's why I wasn't sure about the wavelength until I measured it, it seemed just a littttle greenish, but I figured it might be because I tend to use my blue lasers around the same time. Part of what I'm craving though is that really lovely pale sky blue color, alas it might be that my eyes/brain are just not suited to seeing lasers that way.
 

Snecho

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I really like the 488s but I also keep seeing them all over the spectrum and are iffy in power vs wavelength. It's what keeps me from really getting one.
 

CurtisOliver

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Yep, this happened to me. Our eyes are actually very bad at narrow bands of the spectrum like cyan. I got my first cyan and believed it was 493nm due to the subtle hint of green but in reality is closer to 489-490nm. I know this because I got another cyan laser at around 493nm and it is far greener. And, as RedCowboy said. Different wavelengths and lighting levels will make your perception change. Even viewing other cyans first will change how you view the next one. Viewing the 493nm first will make the 489nm look light blue-cyan. Our eyes are much better at broadband wavelengths than they are at narrow. If you viewed a broader range cyan like your RGB monitor displays you would find it easier to see pure cyan. Just like our phone cameras our brain is trying to work out what colour to display when hit by those frequencies.
 
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paul1598419

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I have actually binned many of these diodes by wavelength. About 20% fall into that 488nm range or below. I gave a laser to my daughter that was doing 487nm. I have one doing exactly 488nm in my collection. So there are your odds. I could be mistaken, but I think Jordan got a spectrometer. He may be able to get you one doing 488nm.
 
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I have actually binned many of these diodes by wavelength. About 20% fall into that 488nm range or below. I gave a laser to my daughter that was doing 487nm. I have one doing exactly 488nm in my collection. So there are your odds. I could be mistaken, but I think Jordan got a spectrometer. He may be able to get you one doing 488nm.
I’m jealous; I wish I had the quantity to bin! You think Jordan would be able to do that? I don’t even know how I’d get in touch since he doesn’t seem to be active on here, but if he could that would be pretty darn awesome. Id love to buy a binned 488 from Jordan along with the 1.6W 405 diode (I guess that’s also a news update, I decided I’m building the 1W+ 405 first, then I’ll think about going 4W+ in blue)

-edit- that reminds me, @paul1598419, I read somewhere that you reccomend against driving this 405 over 1W due to instability, but somewhere else I heard that I should shoot for 1.4 to 1.6... I’ve got to figure out what current to request from Jordan! (Yes I’m a shameful soul without a test load and I don’t want to improvise one at the moment lol)

cheers!
 
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hakzaw1

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At a party I fired up one of my SL Argons @ 488 and the 532 green pointers we were using became a beautiful yellow. I forgot all about that-- I need to do that again and take pics.
But I am sure the 532 in the pics will not look yellow.
 

Snecho

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You think Jordan would be able to do that? I don’t even know how I’d get in touch since he doesn’t seem to be active on here, but if he could that would be pretty darn awesome.
Jordan is out of commission right now. His shop is currently being overseen and run by his friend Augie, on here as @aug.

However, Jordan made sure Augie still provides all the custom services of his shop. You can contact him here via PMs and he should be able to provide everything you need :)
 

Gianakakis

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I have actually binned many of these diodes by wavelength. About 20% fall into that 488nm range or below. I gave a laser to my daughter that was doing 487nm. I have one doing exactly 488nm in my collection. So there are your odds. I could be mistaken, but I think Jordan got a spectrometer. He may be able to get you one doing 488nm.
I was actually thinking of hitting up dtr for a normal 488 and a high WL 488 as I already have an incredibly low 488 messured at 481.7nm! the camera really picks it up like it is a 473:
 

paul1598419

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I’m jealous; I wish I had the quantity to bin! You think Jordan would be able to do that? I don’t even know how I’d get in touch since he doesn’t seem to be active on here, but if he could that would be pretty darn awesome. Id love to buy a binned 488 from Jordan along with the 1.6W 405 diode (I guess that’s also a news update, I decided I’m building the 1W+ 405 first, then I’ll think about going 4W+ in blue)

-edit- that reminds me, @paul1598419, I read somewhere that you reccomend against driving this 405 over 1W due to instability, but somewhere else I heard that I should shoot for 1.4 to 1.6... I’ve got to figure out what current to request from Jordan! (Yes I’m a shameful soul without a test load and I don’t want to improvise one at the moment lol)

cheers!
No, you misunderstood. It is the BDR209 single mode diode that shouldn't be driven close to 1 watt. The multi-mode 405nm diodes can be driven over 1 watt.
 




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