My First IR Build

[jayrob]

I don't know much about IR because I have never built an IR laser...

But I tried it out with a 9mm IR diode from e-bay.

The diode is supposed to be rated for 1 Amp to 1.3 Amps input current, and put out 1 Watt.

Diode: 808nm 1000mw 1W burning IR laser diode. USA 3 day ship - eBay (item 270561475979 end time Apr-20-10 09:50:43 PDT)

Here's what I found...

Current and output:

With a rkcstr red test load, the driver put out 1 Amp from the 18650. (after about 15 or 20 seconds)

With the diode installed, the battery current draw from the fully charged AW brand 18650 is over 900mA's.

The output power was not what I was hoping for with this set up...

* AixiZ acrylic - 420mW's
* 650-G-1 - 650mW's

The 650-G-1, which is coated for 600nm to 1050nm, gave a huge 55% increase in power. But it still was nowhere near the 'hoped for' 1 Watt.

I'm thinking of swapping out the driver for an AMC7135 / 1400...

Especially since this diode is supposed to handle up to 1.3 Amps. (and I doubt' the driver will put out a full 1400mA's)




Other details:

It's scary how this looks dim, but it's actually very bright... If you use your camera on your cell phone, you can see how bright it really is. Because the camera can see the IR...

Quite honestly, I have not put this diode to much testing yet because I am waiting on my IR goggles to get here.

But I did notice in the brief testing, that the diode puts out a line instead of a dot. I believe this means it is multi mode instead of single mode.

But I'm no expert in this area, and would like some input on this if anybody can elaborate.

I tested some brief burning and noticed that I needed to have it very close to the object for really good burning. (like 2 or 3 inches distance)

So that's all I have on this so far, but please chime in with information. Because I am interested in this 'cheap power', but I was not thrilled with the focal point for burning...

Any info?

 

[hugo999999]

from what ive heard you need a FAC lens to focus it properly for distance burning, this corrects the fast axis which is the more divergent of the two

 

[HaloBlu]

Yea it would be caused by the lack of a FAC rather the being multi mode.
http://laserpointerforums.com/f44/some-facts-about-mode-hopping-28456.html its focused more on DPSS lasers but still has general multi-mode info.
I've been trying to help another member doing a IR build Source for 820-860nm diodes? & Looking for visible & IR diodes / modules
Anyone know of a source for FACs? Haven't had much luck finding inexpensive FAC lenses or IR diodes with a FAC built-in. I'm personally interested in 100% invisible wavelengths.

Instead of a FAC, 808 could pump a YAG rod, then I understand you can collimate the 1064nm beam from the rod. Some diodes that claim to be 808 are really a bit off & Nd:yag prefers 808nm. Nd:YVO4 will also produce 1064 from 808 but yag has a longer life.

I love the copper module! Always love your builds.

 

[jayrob]

I just remember talking to Igor a few months back and he was mentioning differences in diodes...

He mentioned terms like 'Parallel and Perpendicular Divergence angles', 'flat rectangular beams', 'photo diodes', and 'multimode diodes' vs 'single mode diodes'...

So that's where I took the terminology from. But I wasn't referring to Tem modes...

 

[Prototype]

Yea it would be caused by the lack of a FAC rather the being multi mode.
http://laserpointerforums.com/f44/some-facts-about-mode-hopping-28456.html its focused more on DPSS lasers but still applies.

If I may, you've confused mode-hopping and multi-mode. A multi-mode diode, which this more than likely is, requires an FAC to properly collimate, yes. A multi-mode diode has more than one emitter per die, resulting in the line output Jayrob noted. Hope this helps.

 

[jayrob]

Hey guys I really appreciate the input...

Does anybody have a line on these 'FAC lenses'? Maybe something we can take right out of a sled??

 

[Prototype]

They can be bought on eBay occasionally, other than that I'm not sure where to get them, although a cylinder lens works just as good, except for the fact that it's rather large, heh. I do know that FAC's are a terrible pain to install, unfortunately.

Edit: Although, even with an FAC, you won't experience a perfect dot like most single-mode diodes give, least not without a slew of other corrective optics

 

[hugo999999]

i was looking for one a while back, but could never find one anywhere

 

[Prototype]

Unfortunately Jayrob, an FAC is usually not found on anything but a laser die, go figure, eh? They're about the size of a human hair, fit right against the face of the die, if memory serves.

 

[RA_pierce]

Nice project there.
I love your copper sleeve.

I have played around with some multi-watt c-mounts, but never finished making one portable... other projects took priority and I never got around to it. Maybe I'll finish my 2W 808 before summer...

Anyway, regarding the short range burning...
You will need a longer focal length lens and a large aperture.
The very short FL lenses like the Aixiz and aspheric lenses do not collimate the beam enough to get very good divergence.
Without beam correction optics, it will be very difficult.

As far as I know, all the high power (500mW and up) IR diodes are multimode. The bare diode output will give you a "stripe" and a FAC lens will shape the beam to more of a square or rectangle. I don't have any pics on my computer... I must have deleted them.

If you want decent divergence or at least a bit better burning range, you will need to make a custom optics assembly.

The most important part is collecting as much of the light as you can.
If you do not have FAC, you will at least need to make the beam as manageable as you can.

A "powerful" lens placed very close to the emitter will keep the beam from spreading too much. A second "medium power" lens can be used to collimate it more effectively. The aperture will need to be as large as possible to accommodate the wide beam.

 

[Flaminpyro]

Nice build I like the use of the AMC7135 driver and the copper/aluminum heatsink
I have not built any IR lasers yet my self as I don't realy think I have a use for one.
You mention the G-1 is custom fit for this installion, is the focal length different ? is the lens in a different placement in the lens case ?
Do you have a plan for this one ?

Later...

 

[jayrob]

Great input!

I noticed that the PHR sleds have thin optics in front of the diodes. I wonder if these are FAC lenses??

Nice build I like the use of the AMC7135 driver and the copper/aluminum heatsink
I have not built any IR lasers yet my self as I don't realy think I have a use for one.
Do you have a plan for this one ?

Later...

Thanks!

I have the measurements for the custom copper module yes, but as you can see, this is a work in progress. I hope to find the right lens set up, and then modify the module design if needed...

The lens is just positioned farther into the lens nut so that it can get closer to the diode. But now I'm learning that I need this FAC lens first. So it's back to the drawing board...

 

[jayrob]

Nice project there.
I love your copper sleeve.

I have played around with some multi-watt c-mounts, but never finished making one portable... other projects took priority and I never got around to it. Maybe I'll finish my 2W 808 before summer...

Anyway, regarding the short range burning...
You will need a longer focal length lens and a large aperture.
The very short FL lenses like the Aixiz and aspheric lenses do not collimate the beam enough to get very good divergence.
Without beam correction optics, it will be very difficult.

As far as I know, all the high power (500mW and up) IR diodes are multimode. The bare diode output will give you a "stripe" and a FAC lens will shape the beam to more of a square or rectangle. I don't have any pics on my computer... I must have deleted them.

If you want decent divergence or at least a bit better burning range, you will need to make a custom optics assembly.

The most important part is collecting as much of the light as you can.
If you do not have FAC, you will at least need to make the beam as manageable as you can.

A "powerful" lens placed very close to the emitter will keep the beam from spreading too much. A second "medium power" lens can be used to collimate it more effectively. The aperture will need to be as large as possible to accommodate the wide beam.

Thanks! I'll have the copper modules available once I get this lens deal figured out...

And thanks for your input...

Hey I saw this:
Double Convex Focusing Lens for 808nm IR laser - eBay (item 130379797402 end time May-01-10 07:50:16 PDT)

Do you think it is what I am in search of for this build?

 

[Flaminpyro]

The FAC lens I believe looks like a piece of glass rod about .015"

 

[Prototype]

http://laserpointerforums.com/f50/560mw-red-635nm-focusing-44365.html

This should help a little.

 

[RA_pierce]

I noticed that the PHR sleds have thin optics in front of the diodes. I wonder if these are FAC lenses??

I'm not sure what you are referring to, but I do not think so.

A FAC lens looks like a tiny fiber optic cable.

It is basically a really really small cylinder lens that collimates one axis of the beam to make a rectangle rather than a "stripe" or "line."

Mounting one by hand seems like a daunting task -- not one I would be willing to undertake myself.
The FAC lens will need to be installed correctly and without touching the die.
Considering the size of the lens and the size of the die, getting perfect alignment will take a lot of time and patience... As well as some IR viewing cards and safety glasses.

Edit: I don't think the lens you linked to is what you need. It just looks like a "normal" convex lens.