Need some advice for my 1W 808nm laser build

ReNNo · Dec 21, 2009

I have 9mm laser module that looks like this...

But I think that I'm losing power somewhere.
Laser doesn't output 1W of power (I don't have LPM but this is obviously).

Lens is far away from diode and just part of light goes through lens. (That is my thought)
But If I turn lens too close to the diode I lose focal point.
I'm using aixiz glass lens.
There is 18mm from front of module to the diode.
Inside diameter is 7mm.

What is the best way to collect all light from diode into smallest spot at about 80mm from the module?

Cylinder lens?

MarioMaster · Dec 22, 2009

Well, how do you know you're not getting full power if you don't have a power meter?

What current are you running the diode at?

Does the diode have a FAC (fast-axis collimator)?

ReNNo · Dec 22, 2009

Diode is running at 1250mA.
There is no FAC with the diode. (It's simple 1W 808nm 9mm laser diode from Boston Laser)

As I can see there is lot of reflection inside module...

I also tried to run diode without module and if I put lens 2-3mm further from the diode some of the light will not go trough the lens.
Just lens must be 2-3mm from the diode so all light can go trough lens...but there is lens holder that prevents all light to go trough the lens.
I also used plastic lens holder and holder started to melting.

Just lens is not enough.

Grix · Dec 22, 2009

As Mariomaster said, how do you know that the laser is not outputting 1W without a power meter?

lasersbee · Dec 22, 2009

ReNNo said:
I have 9mm laser module that looks like this...
But I think that I'm losing power somewhere.
Laser doesn't output 1W of power (I don't have LPM but this is obviously).

Lens is far away from diode and just part of light goes through lens. (That is my thought)
But If I turn lens too close to the diode I lose focal point.
I'm using aixiz glass lens.
There is 18mm from front of module to the diode.
Inside diameter is 7mm.

What is the best way to collect all light from diode into smallest spot at about 80mm from the module?

Cylinder lens?

:wtf:How is this obvious without a Laser Power Meter..
I'm really curious about how you can get an accurate power reading
of an Infra Red Laser beam...:thinking:

If it doesn't have a FAC on it.. it will have huge divergence in both
axis and will require 2 lenses to focus it in both axis. IIRC one of the
lenses is a cylindrical similar to this....

HIGH POWER LASER DIODE BEAM CORRECTION LENS 635nm 808nm on eBay.ca (item 330378426587 end time 22-Nov-09 23:07:23 EST)

Jerry

ReNNo · Dec 22, 2009

Because my 1W laser can burn just as my red laser (380mA).
That means burning black plastic, anything other burns even worse.
1W laser should cut match in half.

As I told you...just one part of the light goes out of module, and lot of light is reflected from inside of module.

About this CORRECTION LENS...
What is size of this lens?
I don't have a penny.

MarioMaster · Dec 22, 2009

It's not easy to have a 1w laser cut a match in half, especially unburnt wood. Even my 60 WATT 808nm laser has trouble burning light colored objects, whilst other items instantly burst into flames.

Since your diode has no FAC, you are indeed losing light before reaching the collimating lens. You will need a small cylinder lens like provided by Lasersbee to correct it.

As for size, you'll have to ask the seller yourself.

ReNNo · Dec 22, 2009

Yeah, I noticed that.
It's impossible to burn wood.
I must paint it with black color.

Yeah, cylinder lens.
But it costs pretty much...about $25 for small lens.
Is there any cheaper way to do that?

HIMNL9 · Dec 22, 2009

something like this ?

CYLINDRICAL LENS, PCX - 4" LONG x 1/8" WIDE x 3mm FL - Surplus Shed

you can cut it at the lenght you need, i suppose .....

ReNNo · Dec 22, 2009

I contacted them so they can calculate shipping costs.
And about cutting...can this be done with glass cutter or something else?

RA_pierce · Dec 22, 2009

There is another thread similar to this somewhere.

1. Near IR is not absorbed well by most organic materials like light colored wood, paper, etc.

2. A multimode diode without a FAC has very high divergence. To correct this, as others have suggested, you need more than one lens.

3. In order to get maximum power output, you need a lens with a larger surface area to collect more of the light. Also, the focal point of Aixiz lenses are very short and will not allow the same focusing ability with such a diode as you will get with a single mode diode like your red.

The module you are using with Aixiz lens will not work unless you use a diode with FAC.

ReNNo · Dec 22, 2009

If my diode is without FAC can I solve my problem with this (CYLINDRICAL LENS, PCX - 4" LONG x 1/8" WIDE x 3mm FL - Surplus Shed) lens ?
It's costs me $9 and I can afford it.
But will this lens work together with glass aixiz lens?

c0ldshadow · Dec 23, 2009

testing

HIMNL9 · Dec 23, 2009

ReNNo said:
Thank for these tips.
I'll give cylinder lens a try.

I'll use some 3mm spacers and glue it to diode can and see what will I get.

THIS POST GO UNDER THE LAST ONE OF ReNNo .....
PERHAPS ALL THE OLD POSTS OF TODAY CHANGED THE POST DATES FROM AM TO PM

EDIT: heard from c0ld, it's due to a change of a MB and it's normal, it can cause some problems but not for too long.

No, wait ..... 3mm is the FL, so you need to put it 3mm from the chip surface ..... you need to use spacers that are 3mm MINUS the distance of the chip from the top of the can .....

wait. searching for draws of 9mm LDs with quotes .....

EDIT: found this one, ReNNo, as you can see, from the reference plane there are two different quotes for the top of the can and for the top of the chip ..... so, the chip is approximatively 1 mm under the level of the can ..... probably better you try with 2 mm spacers or similars

Asherz · Dec 23, 2009

I dunno if everyone has figured this out yet or not, but I think what he means can be explained by this crude diagram

You can see in one of the diagrams not all of the light is hitting the aixiz lens.

Sorry if everyone's already figured this out

HIMNL9 · Dec 23, 2009

Uhm, i suppose not with an aixiz lens (but i'm not 100% sure) ..... all these lenses for aixiz, have a very short FL, and there is the possibility that also a small lens like the one i linked, is too thick for fit it between the aixiz and the diode ..... they usually works well when you have a more large focusing lens, with a FL of 6 / 8mm or more.

For use an aixiz unit, you need to find a diode that have a FAC already mounted ..... or find one of them and mount it in front of the chip, but is a pain you-know-where just find them, not speaking about mount them ..... the direct mounting ones are less than 1mm large, and need to be positioned in front of the diode, and then focused and glued with epoxy resin, and this require a specific mounting setup ..... very difficult at hobby level

Need some advice for my 1W 808nm laser build

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