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Sharp GH04955A2G/ The New 495nm diodes

badboybilly

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If anyone is after a custom host for these new diodes send me a pm,
 



Singlemode Laser

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So,

today I binned the first 10 diodes from my order of 20. I performed a fit to a Lorentzian distribution (first value) and an extreme peak function (second value). Here the results:

  1. | 493.9nm | 493.8nm |
  2. | 493.9nm | 493.8nm |
  3. | 494.7nm | 494.5nm |
  4. | 494.4nm | 494.1nm |
  5. | 494.5nm | 494.3nm |
  6. | 493.9nm | 493.7nm |
  7. | 494.7nm | 494.5nm |
  8. | 494.5nm | 494.3nm |
  9. | 494.2nm | 494.1nm |
  10. | 494.4nm | 494.2nm |
  11. | 494.5nm | 494.3nm |




I will explain the details later, since I have something important to do now. The second 10 diodes will be measured tomorrow. Also a P I Vf curve will be provided.


Singlemode
 
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Nexgen

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Waiting further info from Zraffle, going to send one to sanwu and make 495nm handheld.(if everything goes as expected)
Very impressed with new wavelength!
 

ZRaffleticket

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I'll be sending out PMs when I get home from work. Paul is sending mine back on Tuesday via 2-day shipping, so if all goes well with USPS I'll get them Thursday/ Friday to send out Friday/ Saturday.

Edit:
Its also interesting to see how narrow the variance is with these things. It's really surprising
 
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paul1598419

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That's great, Singlemode. I noticed so far you haven't seen the magic 495nm diode you were looking for. Hopefully it will pop up in the next ten. Looking forward to your current vs optical power measurements and the limit of the current applied to one of these diodes. :thanks:
 

Singlemode Laser

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That's great, Singlemode. I noticed so far you haven't seen the magic 495nm diode you were looking for. Hopefully it will pop up in the next ten. Looking forward to your current vs optical power measurements and the limit of the current applied to one of these diodes. :thanks:
I don't really need to. I was able to pull the 494nm diode up to 499nm with grating feedback and I am really need only 497nm max. So these diodes are what I was looking for!

Singlemode
 

DrMario

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Since the Cyanide green laser diodes seem to have tighter spectrum variability - about 2 - 4nm (thanks Singlemode Laser, for doing the test on the laser diode lot), I may be considering getting one at some point. I like the fact that they're stable in term of wavelength width.
 
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Singlemode Laser

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Looking forward to your current vs optical power measurements and the limit of the current applied to one of these diodes. :thanks:
I allways use a tec controlled diode mount for my measuremts, but I can also use a passive heatsink afterwards as a comparisson in power and wl change.

Singlemode
 

paul1598419

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I allways use a tec controlled diode mount for my measuremts, but I can also use a passive heatsink afterwards as a comparisson in power and wl change.

Singlemode

Since most of these will be in passive heat sinks, that would probably the best way to test it. I use a large copper one, but it isn't actively cooled.
 

Singlemode Laser

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So. Today I did the PIV measurements with a TEC stabilized mount and one with TEC turned off (it wasstill mounted to an optical Table but a TEC is a pretty good thermal isolator). Here the results:

First with the TEC turned on and stabilzed to 25°C





Pretty impressive for my planned application. I can drive the diodes with 300mA and still have almost no kink in the power!




And the TEC turned off:








My programmable current driver can only supply 500mA so I could not get higher. Later I will plot both meas. in one plot to compare them.

Singlemode

PS: How can i decrease the size of the plots and arange them in a row?
 

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paul1598419

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That looks great, Singlemode. I am especially gratified to see that passive cooling seems to work well with these diodes, too. I look forward to your further tests.
 

Singlemode Laser

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That looks great, Singlemode. I am especially gratified to see that passive cooling seems to work well with these diodes, too. I look forward to your further tests.

Thank you Paul. I already new from some companies that override them big time that these GaN diode lasers can take a much higher current than the GaAs diodes (don't really get why but I will find out soon). Seems like their thermal conductance is much better..? I think the max ratings are really for the worst specs: 80°C, no air circulation and heat sink.

In the test without the TEC, the diode mount was mounted on a small aluminum plate. People here tend to use it in a closed pointer housing with less metal to take all the heat. Also my current driver is a lab device and not integrated into the diode mounting. So there is no extra heat input like in the case of a linear driver that has to be taken into account (still impressive though ;))

Are you interested in a test with a housing that is more like the one used in the typical pointers (which I don't have really but can make something similar myself I guess) ?


Singlemode
 

Albert1007xd

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Looking at the results, why do I have the feeling that running them at 100-200mA is just vastly underdriving them??

A.
 

ZRaffleticket

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I believe that would be because Sharp uses the same processes to make the diodes... they have some 505nm diodes coming that are rated for 85mW instead of the 35mW diodes we see now. My bet is that they'll just be selling two lines of the same product, just saying one is better. Probably won't happen for the 495's, but it's probably the deal for the 505s

Flir does it...
 
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Eracoy

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Looking at the results, why do I have the feeling that running them at 100-200mA is just vastly underdriving them??

A.
I too am surprised at it's output. I think I'm going to run mine with a Nanodrive
(DTR Link).

That driver at 350mA would be the most I would recommend. I'm probably going to be using the 275mA setting. That doesn't sacrifice too much power. It'll be on the safe side, and I want it for the color anyway.

If we get more of them, I'll try one at a higher current. How's the wavelength shift from current on these?
 




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