Round Spot from Diode Laser

[claber]

Hi everyone, i have got a red laser 655nm 1.5W from CNI, so beam spot is near to square form, anybody knows how i can make a round spot of that laser?

[MechEng3]

>>Not without opening it up and creating another series of optical compression lenses...costly and time consuming....but it can be done. Anamorphics are good on the cheap....get them unmounted to allow adjustments.

[claber]

it's not problem to unmount it, what lenses needed?

[MechEng3]

The lens calculation will need to be made from the emitter size and divergence. Tell me the specs and I will make a suggestion of lens arrangements to begin with. Thes parts may be difficult to procure....and possibly have to be custom made. Lets start at square one and go from there. I have enough software to manage a very close optical solution.

[claber]

here is the specifications http://www.cnilaser.com/PDF/MRL-III-FS-655.pdf

[LesioQ]

I would say this is as easy as getting square-shaped image of our round Sun using a set of lenses, preferably not using a diaphragm.

Actually laser diode case is simpler - You can rotate it fast !
Piotr.K

[MechEng3]

I think you may have misunderstood me. You would need to take the laser head apart...get to the diodes. I would need the emitter size and length of the laser die itself in the 2 diodes there....possibly one if the layout has changed. They employ FAC lens...good starting point....but it needs to be taken further. CNI may be able to tell you the emitter size without opening it up for now.

[-bart-]

So you want a
1) circular beam, with maintaining 2) power and 3) divergence and 4) beam diameter ?

Then at least one of these four parameter has to give way.

And because you're about to lose power anyway, using a diaphragm is the most cheap and easy method, losing just 21%

You might try coupling it in-to and out-of a fiber.
Probably the 2nd most easy way with off the shelf components.

(Oh, Would you be needing a gaussian beam profile too ? )

[claber]

The emitter size is 4x9mm and the divergence is >4mrad. This data from cni

[LesioQ]

Emitter size should be in micrometers, then 2 orthogonal divergence numbers (slow & fast axis) in the range of degrees or radians, not milliradians.
I guess they provided You with output beam parameters, not emitter data.
Piotr.K