NDG7H75E 532nm CNI Build

[Gryphon]

The NDG7H75E looks like any other generic 9mm diode with a small window and no case pin. At threshold it lases at 530nm and shifts up to 532nm when driven at 1.5A producing 1.3W with a G2. Cramming the maximum amount of heatsinking and a unique diode into the host were the main goals of this build. I didn't dare push the diode to its limits given its price tag so 1.5A is as far as I went.

Behind the solid back half module is a 12mm copper bar I cut down to provide a mounting/heatsink shelf for the driver and switch board.

The module and boards then slide into a copper tube for added mass and to increase the external diameter to match the host.

The final build now has a G8 for less divergence

All the copper has made this small pointer quite solid and weighty for its size.

For comparison the top dot is the NDG7H75E with a G8 and the bottom spot is a NDG7475 with a G8. Pretty close but the NDG7H75E is a little wider.

With the G8 its still manages 1.2W @ 1.5A

Maybe someone braver than me can probe the limits of this diode, but for me this little pointer is perfect.

 

[paul1598419]

Wow! You decided on a very small host for this diode. Can't see you getting much of a duty cycle at that size. It is unusual however to see that much waste heat in something that small. Good luck with it.

 

[Gryphon]

Thank you, its does surprisingly well for the size of the pointer in terms of heat. Lasers of this power in my collection get seldom use so it wont ever see on time long enough to saturate the host. This is one of those lasers I'll pick up and point around for a minute thinking "oh shiny, very power, much wow" then put it back down.

 

[farbe2]

Interestingly, lasertree also offers selected diodes at 530nm and 1,6W. Only with fac as far as I know but it’s easy enough to use and much cheaper than a original nichia diode.
They also have selected 470nm diodes.

 

[Gryphon]

Thier FAC linear is also like $30 cheaper than the FAC square which I thought was odd considering both would need precision placed optics and the diode recanned. Maybe linear is easier/more forgiving?

 

[farbe2]

Linear is more often used in show lasers so its more economy of scale related.

 

[RA_pierce]

I bet those CR2 batteries don't last long.
It's nice to see one of these diodes up and running. This looks like a fun little laser.
Any chance you could get a spectro reading after it's all warmed up? I'm curious how much it will shift as the temp increases.
The datasheet I have unfortunately doesn't have the nice chart showing wavelength vs. temp/current/power that I see for other diodes. I guess Nichia thought it wasn't important.
I still need to finish the optics assembly and host for the diode I bought a long time ago...

 

[Gryphon]

I'm running 4.2V rechargeables in it so its no problem to just pop them back on the charger. Normal CR2's are way too expensive to keep buying.

If it were still in a mount I could get the diode quite hot but as its already in a pointer I was only willing to let it warm up to what I would consider an "over heated laser pointer" temperature. At 125F/51C on the outside of the pointer barrel with a freshly charged set of batteries swapped in just for the spectro test it only increased to 533nm. Not terribly surprising considering the tiny 2nm shift from threshold to 1.3W @ 1.5A

 

[CurtisOliver]

I'm running 4.2V rechargeables in it so its no problem to just popping them back on the charger. Normal CR2's are way too expensive to keep buying.

If it were still in a mount I could get the diode quite hot but as its already in a pointer I was only willing to let it warm up to what I would consider an "over heated laser pointer" temperature. At 125F/51C on the outside of the pointer barrel with a freshly charged set of batteries swapped in just for the spectro test it only increased to 533nm. Not terribly surprising considering the tiny 2nm shift from threshold to 1.3W @ 1.5A

I love that host, but the CR2 is the only thing that annoys me about the CNI/(DL Aurora). Definitely not cheap batteries to keep buying. I've been looking into rechargeable ones for that same reason.