808 nm 1W IR laser diode without FAC, how to focus it?

[Xenom]

Hi

I bought a infrared 808 nm laser diode at very low price (15$ and free shippings), i have tested it and it works, but i discovered that the DL doesnt have FAC (fast axis correction), alost i suppose it.
I didnt know the existence of FAC until now.
I read this thread on this forum: http://laserpointerforums.com/f40/need-some-advice-my-1w-808nm-laser-build-46455.html and i think that the DL is the same or very similar of the Renno's one.

With no optics, che beam of the laser appears to be like a line, with high divergence on an axis.

I tried with varius optics taken from SLED/laser pickups of dvd and cd player/burners but no one can collimate the beam well.

I suppose i need a specific optic like cylinder lens to correct the high divergence on the axis.

Any suggest?

PS: i'm from italy and sorry for bad english

edit: by the way i need particular lens for 808 nm wavelenght or a common uncoated (or coated for 650/750 nm from laser pickups) glass or acrylic lens works well?

edit again: my goal is to make a true burner laser even with fixed focused optic, with a short focal lenght. I do not use axixs module for this DL. I mounted it on a heat sink, i will mount the optic home-made in some matter.... :\

 

[Xenom]

up... any suggestion?

 

[nikooo777]

hey ciao!
i have one 300 mW IR laser and have the same "problem", i just gave up and ended using it in short ranges (30 cm max i'd say) using 808 nm lens that i got from a special module on o-like:
9mm diode housing with glass lens for red laser or 808 nm laser [OL9mm] - $7.20 : Welcome to O-Like.com, Your source for laser products

those lenses work better than normal ones, so seemed to me!

saluti dalla svizzera!

Nikooo777

 

[Cyparagon]

A regular lens will work okay. The dot will still be a line, just much smaller. If you want to get rid of the line, you'll need more optics, money, and patience. Better to just live with it or upgrade the power.

 

[rhd]

Cyparagon:

Could you in theory do the following to get a "dot"

1) Position a cylindrical lens in front of the diode to get the Y axis "tamed" so that it is still diverging, but at the same rate as the X

2) Position a regular (concave?) lens after that, to "tame" both axis to a dot?

IE, two lenses. One cylindrical, one not.

 

[Cyparagon]

Yes. That first lens would be the "FAC". It either needs to be mounted on the die, or the collimated beam will be large. There are a few ways to do it.

 

[Xenom]

Thanks all for replies

I tried to get the beam focused on a small dot, viewing it at very low power with a phone cam, with standard lens of various kind, all taken from cd/dvd players/burners pickups.
But i think there is a lot of power loss, cannot burn black plastic very well :|

For the best performance, without using a external FAC, what lens must i use?
edit: do those lenses (from pickup i mean) work with 808 nm? and the focus lenght and diameter are good or bad for my application?

hey ciao!
i have one 300 mW IR laser and have the same "problem", i just gave up and ended using it in short ranges (30 cm max i'd say) using 808 nm lens that i got from a special module on o-like:
9mm diode housing with glass lens for red laser or 808 nm laser [OL9mm] - $7.20 : Welcome to O-Like.com, Your source for laser products

those lenses work better than normal ones, so seemed to me!

saluti dalla svizzera!

Nikooo777

bella lì!
Very interesting product at low price... can it dissipate 1-2W of DL's heat?
Then you could focus the beam in a very small dot without the help of FAC, using that 9mm case?

Visto che mi capisci lo scrivo anche in italiano così riesco anche a spiegarmi meglio
Tu possiedi quel modulo e riesci a collimare perfettamente in un punto molto piccolo il fascio? potrei anche pensare di comprarlo.. quanto costano le spese di spediz in italia?

thanks all