Sharp 490nm GH04850B2G 55mW Laser Diode

[Serveurperso]

I wonder what I get if I mix this cyan with just enough red... A strange bi-chromatic white ?

 

[ZRaffleticket]

Actually, the red would lean on the pink side. If you want a more pure white with ~488nm, you're looking for a 589nm (yellow) laser instead:

 

[Serveurperso]

Thanks for the picture ! It's fun, with a good balanced bi-chromatic white as lighting we should see "like a daltonian", It deceives the eye by making white but it is not white.
Normally the pink is a white with too much red. what it look with less red power ?

 

[paul1598419]

Thanks for that detailed explanation of the flexdrive, Jordan.

 

[ZRaffleticket]

well, changing the volume of red won't help in this situation.

Look back at the color gamut chart and you'll see a clearer picture of why:



The line from 488 -> 589 passes through a much more pure white than 635 or 650 do. You'll either have something too red, too magenta, or too blue if you pair it with a red.

 

[Serveurperso]

Yes your right.
490nm is the most beautiful wavelength I hope Jordan has ordered a lot !
it's the perfect #00ffff cyan (https://academo.org/demos/wavelength-to-colour-relationship/)

 

[Eracoy]

well, changing the volume of red won't help in this situation.

The line from 488 -> 589 passes through a much more pure white than 635 or 650 do. You'll either have something too red, too magenta, or too blue if you pair it with a red.

That is an excellent visualization of why some combinations of colors can give white, and which are closer to a true balance. The gamut of what colors a laser combination can make is the section between the input lasers which can vary from 0-100% power. In the case of two lasers, this is a line between the colors on that graph. If three lasers are combined, there will be three points along the curve. The triangle formed will be the colors the combined beams can produce. Usually projectors have a balance of red, green, and blue. This makes a wide triangle, and thus offers many color choices.

I like that this combination of wavelengths shows that three colors are not necessary to form a white-appearing beam.

 

[Serveurperso]

On this one the complementary wavelength are a bit shifted.
Perception of eye is relative. if I get a near 590nm aqua and I use a very cold red 635 I get a near white for eyes.

 

[Dr.Laser]

These are the readings of the 6 diodes I sent to CNI.

486nm
487.07nm
489nm
489nm
490nm
491nm

I’ll probably have both the 486nm and 490nm built into GLPs.

 

[Serveurperso]

About glow in the dark painting : it work best at 405 and 445nm

- 405nm : resulting color is pure green from panel, like the casio fluorescent light converter with 445nm LD.

- 445nm : resulting color is a blue-white because blue + yellow/green from panel

- 462nm : resulting color is blue

- 490nm : must work with less efficient conversion... I test soon lol

- 505nm : I can see a bit of afterglow !

- 520 nm : noting

- 1000nm infrared laser : I can see the dot (no afterglow)!

 

[RedCowboy]

These drivers look good for use with the sharp 490. Yes I know there's a thread for these, but I like being able to click and order so here it is on ebay.

https://www.ebay.com/itm/Astral-Pic...050504?hash=item25f2212d48:g:8FQAAOSw8hhawSTj

 

[Serveurperso]

The only driver I trust for any singlemode LD is the boost/buck nanodrive from lazeerer.
All other killed diodes when the switch make noise on input (overshoot)

Also a boost-only driver is dangerous for some lower voltage LD if the battery get a bit overcharged.
Also on graph there is no soft start and we can see an overshoot on startup

 

[paul1598419]

These are the readings of the 6 diodes I sent to CNI.

486nm
487.07nm
489nm
489nm
490nm
491nm

I’ll probably have both the 486nm and 490nm built into GLPs.

Looks like their results closely reflect mine. Glad to see you got a couple low wavelength ones along with the ~490nm ones. I wonder what current they used too test these as a low current will affect the wavelength if driven harder in a pen host.

Even if you keep the current low, the lack of heat sinking in these pens will allow the diode to get warmer than a heat sinked one would.

 

[Dr.Laser]

Looks like their results closely reflect mine. Glad to see you got a couple low wavelength ones along with the ~490nm ones. I wonder what current they used too test these as a low current will affect the wavelength if driven harder in a pen host.

Even if you keep the current low, the lack of heat sinking in these pens will allow the diode to get warmer than a heat sinked one would.

I don't have an exact number for current but I always ask them to do the test around threshold current..

The output of my GLPs are always around 10mW and heat is not a problem for the non-dpss GLPs. I did a test on my GLP-495 and the wavelength increase 0.2nm over a period of 5 minutes of continuous running and the body doesn't even get warm.

 

[paul1598419]

I don't have an exact number for current but I always ask them to do the test around threshold current..

The output of my GLPs are always around 10mW and heat is not a problem for the non-dpss GLPs. I did a test on my GLP-495 and the wavelength increase 0.2nm over a period of 5 minutes of continuous running and the body doesn't even get warm.

Ah. That is good to know. At such a low power the module is likely providing all the heat sinking you need for these. Most of the people who are getting these diodes are driving them at 275 mA, which is far beyond threshold current. They will heat up and the wavelength will shift dramatically if not heat sinked well.

 

[aaronnoraa]

What lens is recommended for this diode? From what I've gathered, with the 495nm diodes the acrylic or 2 element lenses seemed to be the best at avoiding the square artifact that occurred when using other glass lenses with that diode, do the 490's have that same artifact?

Just wondering since I'm about to order and noticed that neither the 2 element nor acrylic are offered with these diodes on DTR's site and I'm wondering if perhaps there is a reason for that...

Looking forward to having this beautiful wavelength!