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Questions about Building IR laser...

RA_pierce

RA_pierce

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Sep 16, 2007
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I understand IR has very different properties from light in the visible spectrum, so I have a few questions regarding what is required to build one:

+What power level diode can I expect from a CD burner? DVD burner? 5mW green?
+What wavelength do CD and DVD burners use? Is it the same as the 808nm used in pointers?
+What kind of optics are required to collimate the beam?
+Where can I find the least expensive, but most effective for price, IR eye protection?
+Is the time and money worth building an invisible burner?

Thanks...
 





CD burners will range from 50mW for a low-speed to 150+mW for a high speed. The 48x burner I recently tore apart has an estimated 180mW CW output ability. DVD burners have about the same range, only in red.
CDs use 780nm wavelength, while DVDs are 650nm.
A standard Aixiz lens (as most optics) can work efficiently at 780nm as well.
As far as IR protection, I haven't found anything trustworthy for less than $150-$200US. Maybe someone like Pseudo would know better on this.
It may be worth the time and money, depending on what you are looking to do with it. IR and near-IR diodes are much cheaper, so it's an easy way to get a low cost burner. 780 and 808nm are considered near-IR because you -can- see them, but not very well. They're both like a very deep red.
 
Thank you... And a few more questions:
If CD burners use 780nm diodes will I still need IR protection?
And are they open diodes?
I want to make a red burner but I think an IR (or NIR) burner would be cheaper, and I'm not really concerned about visibility. I recently tore apart a DVD drive and extracted the Red and IR diodes. I killed the IR diode by hooking it up directly to a couple AAs. Do they require lower voltage than 3V or was the current just too much?
I'm planning on soldering the diode onto my half broken green's driver and plugging it into a flashlight (2 AAs) or the green laser's body (1 CR123).
What is the max amount of milliamps I should use?
And as far as heat sinking, what do I need? I can't open the heat sink of my green laser (without risking breaking it) so the only thing I really have is a cheap red laser's heat sink with a collimator.
 
Whichever you use, a high-powered laser is still a high-powered laser. What's worse is the limited eyewear for the 780nm. Yes, you still need protective goggles, but I have yet to find a cheap pair that has a rating of OD3-4 for 780nm.
Most of the diodes I've harvested were closed can, but I have found 2 that were open. That depends on the manufacturer and drive speed.
As far as the blown diode, you probably did feed it too much current. The big issue with any laser diode is current, and not voltage. It simply happens that to provide one with its optimal current, it usually lies in a certain range of voltages. I strongly recommend building a cheap LM317-based table supply. If you can, go to a place like Radio Shack and pick up one of their 25ohm potentiometers, the LM317 chip, and the rest of the components needed to build DDL's driver circuit. The range of resistance you want for most laser diode tests is 30ohms max to 3 ohms min. This will give you a wide range, supporting low power diodes as well as pushing the higher power ones to the limits. If you don't want to put more risk to your higher end diodes, make sure the resistance can't go below 5 ohms. Here's how this breaks down:

Blu-ray LDs and 5mW red LDs want between 25-50mA depending on the diode. If you can, find the appropriate data sheet and take the Iop rating. If not, start at the adjustable supply's lowest current setting (highest resistance). Use an ammeter in series with your laser diode. From the point where the laser truly kicks in and forms a beam, turn up the current no higher than 10mA. This is a well-respected safe zone for operating your lower laser. Pushing it above this will add risk, but may also increase its output power. I don't recommend breaking 250mA for the higher powered 16x DVD burner diodes, or the GB red diodes.
This said, green pump diodes often require more current than you would expect. Some of those green drivers may spell a fast death to a red LD.
For a good heat sink, I recommend getting a low-cost TEC off of eBay. Many people are offering them for under $20. Remember, heat lowers a laser's output and increases its current draw. This is another reason a regulated current supply is a must. For a housing and simple heatsink, the Aixiz modules do well enough that I use them for my DVD-harvested red diodes. I keep the run-time low on them, however, unless I have the module sitting on a TEC.
 
Hmmm... I see. That helps a lot. Thanks. The eye protection seems to be a bit of a problem.
I need parts now. Do you have any CD burner brands/speeds you would recommend? And are CD burners any cheaper than DVD burners? All the good DVD burners I've seen are more than $70 and I'm trying to keep the cost low.
 
I would recommend staying with the DVD drives, possibly ordered over the internet. If you can't do this, you're probably limited to the luck of the draw. Some of the 48x burners I have opened use different cans, and the Aixiz module supports only the one design. So far, I have had excellent luck with drives from LG and Pioneer. If you get to a small computer shop, you may be able to acquire a cheap used burner. Retailers probably won't give you much of a discount over DVD burners.

Another concern is the focus of a near-IR beam. Since the laser is barely visible, you may have a hard time properly adjusting the lens into a tight dot. This may cause problems if you intend to use this laser for burning.
 
I might see if I can get a used DVD burner then. When I adjust collimation, can I still use a digital camera to see the dot more clearly?
 
For the IR, you can get close with a good digital camera. The problem here is that the light will be intense enough to bleed across pixels on your digital camera's CCD even if you do have a high resolution viewscreen along with it. You may need to turn the power down to barely above the lasing threshold, and you may possibly need an optical attenuator of some sort so the camera can properly display the laser's output.

If you do get a used DVD burner, try to find a high speed (8x-16x) burner. This way, you'll have a good 650nm red diode from the DVD side to play with, and that can be easily focused by eye. You'll probably also have an IR burning diode in there as well, so it's double the value to a laser enthusiast. :D
 
Yeah I was thinking about that too... 2 diodes in one package is a good deal.
When I extracted the IR diode (that I cooked), it was pressure fitted into some kind of a small die-cast-ish housing with some sort of glass optic in front of it. I could never get it out. Extraction is usually my biggest issue; when I took out the red diode, I cracked the lens in the emitter window. Any tips on extraction?
 
Don't throw it out, even if you crack the window on the laser can! I made that mistake once, too. If you're really careful with a diamond wheel on a dremel and a set of precision clamps, you can cut the can open and turn it into an open can diode. I've done this numerous times for damaged/broken/underpowered diodes. Just be careful, because you'll need to clear away all the debris and metal splinters without tearing the 1/15mm wires from the diode to the connection posts. For the difficult housings, I use the same tool to cut small notches in the original heatsinks until I can split them apart and remove the diode, usually untouched. You need to have either a brace or a very steady hand, but it can be done.
 
That's what they all say. It's said after the 3rd, 4th and 5th time and so forth.
 
I know this is old but:

I just got an IR diode I ordered from ebay seller located in china. fast shipping and CHEAP

[highlight]200mW IR diode at 10 dollars!!!!![/highlight]


Hes not currently selling anything, but once in a while search 200mW on ebay, the seller is snoctony.

He sells 500mW and 1Watt diodes too! its preety cool


I hate How I cant see my laser tho...

sigh, I like senkats diodes better...
 
The specs say TO5 package... But it shows a picture of what looks like a 5.6mm diode. Which is it?
 
RA_pierce said:
The specs say TO5 package... But it shows a picture of what looks like a 5.6mm diode. Which is it?
Click to expand...


You are looking at the 500mW and the 1W. those atre TO-5. The 200mW's are TO-18 (5.6mm) and they DO fit in aixiz modules.


ENGLISH!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! >:( >:( >:( >:( >:(
 
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