My laser beam has no power! why?

Today i received my aixiz module. I replaced LD with mine, grabbed from 22x LG GH22NS40 writer and powered from driver. My laser beam has no power!!! First i tried at 150mA, and put my hand 10cm in front of it. Nothing. I doubled current and tried again. The same ... just a nice red spot on my hand. Even focused, no power, just a small red spot. Tried more power, 410mA continuous 30 seconds. My hand doesn't seems to feel some heat but ... the aixiz housing become warm. No doubt, the driver is working, but my led NO!
I tried with my 650nm goggles:
- when look into aixiz spot 2m in front of me, i can see it (smaller then without goggles, but still visible)
- when my LD is used, I CANNOT SEE THE SPOT! The beam Is so weak. Only without goggles is still visible!

What to do now?

I know that this LD have 3 pins, one of them not useful (for photo diode), one for dvd burner, and ground. Is not possible that now, by mistake, to power photo diode and not the laser one? I don't know if is matter, but I measured internal LD resistance (between + and -) and is 19-20 Ohm! I used pins and voltage as in picture attached.

I would like to know for sure if i was wrong in the past when i powered my diode (just 2-3 times, less then 20-30 seconds each) by 2 x AAA duracell alkaline MN2400 batteries?

alx

And another question: is normal that for LOC diodes the beam (when is focused) to look like saturn planet (a very oblate ring having in the middle a spot)? Aixiz original module is revealing a spot on the wall.

I have attached a picture to show how is looking my laser on the wall (2 m in front of me)
- on the left: my oblate ring with spot in the middle
- on the right is spot produced by original aixiz.

alx

kkt, as to power: I just shined a 200mW red laser on my hand from 2" away, beam diameter about 3mm... did not feel hot.

You cannot judge a red's power by feel, because your skin does not react well to that wavelength. BUT - I do not focus my 100mW blu-ray on my skin! that stings right quick.

That said, you may have a damaged LD - it should be very much brighter than the original red from Aixiz (if I understand right what you have).

edit: just saw that about batteries wth no driver... that's a no-no, it may have killed your LD.

DanQ

hi danq,

ok, probably you are right... but being first time i've made it, you know how it is: you need something to compare.... anyway, i didn't know that few seconds on alkaline battery will destroy my LD.

how about the beam? did you used/see beam of LOC? is like saturn ;-) or like a spot?

alx

The beam produced is typical for LOC diodes.

Yep. A lot of diodes I've seen have a line through the dot like that.....I wouldn't say it looks quite like saturn though. There was a macro shot of the laser dye that explained why that line shows, but I wouldn't know where to begin to find it again. :

Btw, the photodiode doesn't emit any light.

Your diode could be dead from a number of reasons: direct drive (though mine is in it's second year like that) , using an Ohm meter on it , static , and stuff like that.... :-/

Switch said:

Your diode could be dead from a number of reasons: direct drive (though mine is in it's second year like that) , using an Ohm meter on it , static , and stuff like that.... :-/

Click to expand...

but you have no doubt that I used the right pins to power it (shown in picture above) and also that the LD is dead, right ;-) ?

regards,
alx

DanQ said:

You cannot judge a red's power by feel, because your skin does not react well to that wavelength. BUT - I do not focus my 100mW blu-ray on my skin! that stings right quick.
DanQ

Click to expand...

Interesting. Do you want to say that human skin react/feel better the heat coming from a blue-ray diode than heat comming from red diodes even blue ray has output power smaller then red LD? I know that latest blue ray can output 100+mw and red diodes more then 250mW.

alx

kkt said:

Do you want to say that human skin react/feel better the heat coming from a blue-ray diode than heat comming from red diodes even blue ray has output power smaller then red LD?

Click to expand...

yes - depending of course on how much different the powers are - but that's only for human skin like mine ;-)

I just now tried it... 100mW blu-ray and 200mW red, both focused to a spot about 2mm diameter, from 6" away. The blu-ray stung after about 5 seconds; the red felt warm after 20-30 seconds.

A factor that might affect my results: I am very pale, pink to some degree. The red light seems to diffuse into a wider area under the surface. Results may vary with skin color?

DanQ

A "dead" laser diode does not produce any light, nor does it draw current. It would be like connecting power to a rock -absolutely no current draw or output.

A "blown" laser diode can still produce light and can still draw just about any current you feed it. In most cases, the blown diode just produces a weak to medium red glow, like a dim LED. In some cases, it can still lase, but at a much reduced power level.

Dead laser diodes can be made by physical damage (usually during extraction), static discharge (wall to wall carpeting and diodes don't mix) and by HEAVY current loads (I tried to power my first laser diode straight off of a 9 volt batter)

Blown laser diodes are almost always made by runaway current draw when connected directly to a battery. This can happen VERY fast. One time I was just "doing a quick test" by connecting a DVD burner diode to a couple of AA batteries. The first time I connected the diode, everything was fine for the couple of seconds I had it connected but, after breaking the connection from the batteries, I immediately reconnected it and it blew, phffft -instant LED. I'm sure reconnecting it the second time, right after it was already connected, created a current spike -bu don't ask me to explain the theory.

You can blow a laser diode by overheating -letting it get too hot without a heatsink.
You can blow one by applying current using the wrong polarity.

You can also blow an LD by "aging" it. -You accelerate the age or shorten the lifespan of an LD by powering it above its specs (which most of us do, to make them burners). The average DVD diode will last for many years inside it's DVD drive, never drawing more than a 140ma, but you take it out and regularily subject it to 300 to 400ma and you can count it's lifespan in weeks or months (depending on how often you use it).

There are a LOT of ways to destroy an item as sensitive as a laser diode, but there's really only one way NOT to ruin one and thats to use a current regulator circuit, commonly called a "driver". There are a number of members who sell very good ones, both adjustable for any diode and current draw or tailor made for your particular diode, upon request. You can also make your own driver with as little as 4 electronic parts you can buy from any Radio Shack for as little as $5 bucks total.

Hope this helps,
SK

SuicideKing, that is an excellent post you made there. Very clear and succinct +1 rep

i built a LOC and it did the same exact thing :-/ mine was a LPC 20x.. but the blu-ray (i ran them both on the same driver to 'check it') burned like a b!tch where the LOC could not burn anything..

blu-ray ~ 130mA
LOC ~ 130-430mA

(rckstr adj driver)

perhaps booth we killed the red LOC diode with static electricity, or by powering (in my case) direct to 3V alkaline battery.

but i keept your hint about blue-ray. what diode are you used? Harvested from PHR-803T?

regards,
alx

The line through the dot is normal.  And the way you can easily tell if the abnormaly is on the lens or the LD is by simply turning the focusing lens while it's on and if you see the "shape" turn too then it's on the lens, but if it stays, then it's the diode.  

You didn't use the driver from the aixiz module did you?  Because in that case it won't push more then 5-10 mW using 3V, but you said you tried different currents so I assume you're measuring from the driver out-put under a test load and not the input of the driver right?  

If you put the diode directly to 3V without a driver then depending on the diode it will damage it, some last longer then others.... *sigh, Kipkay Kipday.  

Unless you're a black person and you're shining your red laser focused on the top of your hand, then you most likely won't feel a thing because of our skin and blood being light and red defuses the light which is why it's easy to see the light pass through the palm of your hand, to where as green or other colors will get absorbed by the skin and you will feel the burn (given it's hight enough power) and you can't even see the light through your finger.  

perhaps you could find some cool DIY stuff here: http://stonetek.org/shop/

Ace82 said:

You didn't use the driver from the aixiz module did you?  Because in that case it won't push more then 5-10 mW using 3V, but you said you tried different currents so I assume you're measuring from the driver out-put under a test load and not the input of the driver right?  

If you put the diode directly to 3V without a driver then depending on the diode it will damage it, some last longer then others.... *sigh, Kipkay Kipday.  
/

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is not the lens, is not the driver! no doubt! the shape on the wall is changing. the driver is build by me and is working like a charm. is not necessary to use voltmeter or ampermeter, to know exactly the output current of the driver. Is enough tho know some electronics and how to measure the circuit resistence (offline) and voila. forget about this problems and also about stonetek shop.

I said that (and i suppose that is the cause of my problem): BEFORE to power my LD using my driver, I tested 2-3 times (max 20-30 seconds each) powering direct from 3V ALKALINE BATTERIES! In that case, like now, my LD has THE SAME SHINING beam! No more no less! Now , i am surprised to discover how sensitive are this diodes when powered without a driver! I read on other posts that red diodes can be powered for a short time direct to 3V batteries. But they don't specify there what exactly mean "short time" I assumed to be 20-30 seconds! It seems that i was wrong!

To be more specific: how long can be powered a red LD from alkalines, without destroying it (safest time)?

alx

alx said:

perhaps booth we killed the red LOC diode with static electricity, or by powering (in my case) direct to 3V alkaline battery.

but i keept your hint about blue-ray. what diode are you used? Harvested from PHR-803T?

regards,
alx

Click to expand...

that is possible.. and yes the blu was a PHR

Ace82 said:

You didn't use the driver from the aixiz module did you? Because in that case it won't push more then 5-10 mW using 3V, but you said you tried different currents so I assume you're measuring from the driver out-put under a test load and not the input of the driver right?

Click to expand...

im using a rckstr adj high range (130mA-430mA) red sucks dosnt burn/light matches/pop balloons/meltslashcut electrical tape etc.. (of course all blacked up) where the blu would cut tape/pop balloons/burn skin/light matches etc.. ran blu at ~130mA and LOC starting at ~130mA and going up to ~430mA still nothing..