185ma PHR MXDL duration testing

I am rather bored over the holidays atm, so have decided to start sacrificing some of my PHR diodes to testing.
The build I am using is the 3xAAA MXDL with a jayrob heatsink and a flexidrive set to 185ma for the PHR-803T diode. It is measuring 134mW on startup. It is using an Aixiz acrylic lens with the back cut out.
This diode has had about 20-30 2 minute cycles over the last 3 months or so. And lately I've begun some duraion tests.
Over the last four days it's done 6 cycles at 8 minutes, 1 at 9 minutes and then another at 12 minutes. In the first few 8 minute cycles the power rose to 140mW before I turned the laser off, but now it doesn't go above 136mW. The heatsink barely gets warm but I stop because I want to build this up and see how long it can last. I'll post some pics later and more results till this diode is dead.

I still have my PHR in a leadlight clone, dated Nov.4.08. Its been running at 177ma and putting out 180mW and 185mW after warmup with an axiz acrylic. This is a pointer which I play with total approx.15mins a day, and still putting out the same as the day I sealed it

Its the only one I have putting out 185, but its still going strong with regular daily use


Best of luck with the tests.

Wow, thats a good laser, and sounds like its going strong. I can't wait to see some BR over 160mW. All the PHR diodes I have had have been quite under ma ratio. My personal leadlight PHR is 125ma for 100mW and gets rather hot after a minute or so. I just use this on occasion, maybe 10 minutes a week.

nvmextc;

According to Nichia literature, the lifetime of their laser diodes is measured when the current to rated mw output is raised by ~30%.

So the fact that your laser diode is outputting less mw @ the regulated current is a warning sign.

LarryDFW

Thx Larry but I'm not to worried, I just want to see how this build affects the life of the diode at high currents and durations and plus If I measured this without a lens it could be closer to 180mW I believe.

Now I've been keeping this thing on for a while lately and it's starting to do some damage, but it's getting very strange. It's had 4 more cycles @ 12,18,14 and 23 minutes. Each of these times the power rose from 135mW to 140mW. But now it starts getting wierd.

Next time I turn it on it starts alright, but after 12 minutes it's 100mW and 14 minutes its 85mW. I decide to change the lens now, it's melted in areas and can't focus far away anymore, the ouput looks very messy. Upon doing this I discover most of the problem is not the lens but maybe the diode window? Look at pics below to see the raw ouput.

Next time it turns on it starts at 85mW, after 3 minutes 80mW, after 13 minutes 83mW, after 16 minutes 89mW, after 27 minutes 96 mW, after 32 minutes 98mW, after 36 minutes 99mW, after 52 minutes 102mW.

Next time it turns on it starts at 100mW and after 18 minutes is 104mW again.
I'm waiting for the batteries to charge again so I can get mroe results up, I am just waiting for this diode to die now.
I hope this information is easy for others to read, I thought a graph would complicate things.

As I was testing the SF-AD112 sled diodes, I could trace the breakdown of the mirrors. I was shining the laser onto a wall in the garage without any optics. The diode was pressed into a module and the module was in a large heat sink. The module caused the light to be circular with the "trademark" flat line of bright light in it.

First small spots of "concentric circles" would develop. These looked like what the surface of water looks like when you drop something into it.

Sometimes secondary "bubbles" would also appear.

Next, these would "grow" and sometimes more would appear.

Next dark spots with rough, irregular edges would appear.

It would go LED soon after the dark spots appeared.

This process was very similar from diode to diode.

Peace,
dave

Daguin, that is exactly what's happened here I think   I haven't been watching the output consistently but looking at it now and then to see what is happening.
That picture above is the last one I took, so the worse dark spot stage
This picture below is about 2 hours beforehand
And before I started this duration testing I know it was a perfect output.
This is very interesting to me, so far I have concluded that this heatsink/host combination is very efficient in dissapating the heat, but the diode itself cannot last at long durations for this amount of current or power. The diode is losing power and fluctuating strangely, and the window/mirrors are obviously getting destroyed then.

Next round of cycles...
On @ 103mW, after 30 minutes 108mW
On @ 106mW, after 50 minutes 109mW
On @ 109mW, after 75 minutes 115mW
On @ 113mW, after 90 minutes 116mW

The whole top section of the host gets a bit warm after 30 or so minutes, and after 50 minutes you can really feel the warmth in your hands.

The power output keeps increasing slowly like this, very strange I think. There are more "bubbles" appearing and it looks like alot of the dark solid mess that was there before is turning into a collection of bubbles.

My camera doesn't see it perfectly but here are some pics of the output atm
Without lens

With acrylic lens