Sharp GH04955A2G/ The New 495nm diodes

[paul1598419]

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

I don't think another closed test to simulate a pointer's heat sink is necessary. I can see all I need to know from what you did already. Though most pointers don't use a large mass of aluminum to remove heat from the diode, I use more than most and can see from the diode's spectral response that it doesn't get very hot in the time that I use it. I'm glad you have been able to do this testing for us as it is outside your need to know parameters. :thanks:


Edit: As far as wavelength vs current, it seemed to me the greatest WL shift came from heat and not current. This doesn't mean you can crank up the current without sufficient heat sinking. As long as you can keep the diode's temperature down, it shouldn't shift by that much.

 

[Singlemode Laser]

How's the wavelength shift from current on these?

As for all GaN diodes it is around 1nm per 200mA (if the extra heat is effectivly removed) and ~1nm per 20°K. At some point the this relation becomes nonlinear (when the thermal rollover starts) and is usually higher but also a sign that you close to kill the diode.

Without a proper heatsink a high current produces addotinal heat and the two effects on the wl have to be combined.

Singlemode

 

[evans965]

I see that people on this forum has got 495nm laser diodes would anyone like to sell me one thanx.

 

[paul1598419]

I see that people on this forum has got 495nm laser diodes would anyone like to sell me one thanx.

Send lazerman121 a PM. He has some, but hasn't started selling them, as far as I know. Also, Singlemode Laser will be selling off at least ten....maybe more in a few more days.

 

[BowtieGuy]

Paul and Singlemode, thanks to both of you for all your work and testing on these diodes, they definitely look hardy; it looks like ~275mA is still a good, safe setting for these. :yh:

 

[paul1598419]

That's the current I'm using. As soon as it gets here from DTR. Hope he ships it soon. :cryyy:

 

[BowtieGuy]

Paul, which driver are you going to be using?

 

[paul1598419]

A Nano Boost Driver. I ordered it last Wednesday and he printed the label on Saturday, but it hasn't gone out yet. I guess he's busy, but it should go to the post office soon. I would hope so, anyway.

 

[DrMario]

It should be coming soon - DTR was / is swamped with heap of orders right now. I finally got my 450nm and 505nm laser diodes yesterday (and assembled the blue laser).

 

[styropyro]

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

Thanks for all the awesome data! Looks like these things are pretty powerful too.

What current was going to the diode when you put each of them on the spectrometer? Sorry if you already stated it, can't seem to find it...

Edit: also if you have any left for sale, I'd definitely buy one!

 

[paul1598419]

@ZRaffleticket

Your package went out at 11:30 A.M. Pacific time today.

 

[ZRaffleticket]

Awesome! Thank you Paul. I'll let you know Friday how the diodes are, and on Saturday I'll get them in the mail to my buyers.

Hopefully I can get a few pics Friday/Saturday; so far my phone could handle color accuracy for everything I threw at it. I also have a very nice host coming in from Rich.

 

[paul1598419]

Seems we both have hosts coming from Rich. I plan on putting mine in his host too.

Damn! I just tracked my host and it is delayed indefinitely. They'll let me know when it is coming again once whatever is holding it up gets resolved.

 

[Singlemode Laser]

Thanks for all the awesome data!

You are welcome. I received a lot from this forum and it's members so I just try to give some value back to them.

What current was going to the diode when you put each of them on the spectrometer? Sorry if you already stated it, can't seem to find it...

Edit: also if you have any left for sale, I'd definitely buy one!

100mA (~45mW output power) and a heatsink temperature of 25°C.

I will open a sell thread soon, when I measuremed them all and decided which one I will keep for myself. I don't take any reservations but will favour
selling to honourable members of this forum who hadn't the chance to buy one of these yet.

Singlemode

 

[Dr.Laser]

I sent 4 diodes to CNI and the results came back as following :

494.6nm
494.9nm
494.9nm
494.9nm

All the four tested at 30mW. They are pretty much a spot on 495nm, I was hoping to see a bit of variety in the wl but still can’t complain. I’ll have one built into a GLP as usual and I’m thinking about a PGL running at 300mA.

 

[jnrpop]

I sent 4 diodes to CNI and the results came back as following :

494.6nm
494.9nm
494.9nm
494.9nm

All the four tested at 30mW. They are pretty much a spot on 495nm, I was hoping to see a bit of variety in the wl but still can’t complain. I’ll have one built into a GLP as usual and I’m thinking about a PGL running at 300mA.

Really consistent results dr.laser, thanks for sharing :beer:

Just for knows sake, do you get cni to set all your glp's @ 5mw?

J