@OrturTech Thank you for that helpful input, to me it is both honest and welcome . . . I do understand the the underlying laser diodes themselves always generate a rectangular output [typically in a 2:1 ratio] and that to achieve a square focus some clever asymmetrical lenses have to be accurately located in front of them, and in the case of multiple diodes [e.g. 10W & 20W optical output lasers] polarised and then combined with high quality optics . . . all before they hit the final focusing lens(es).
I have read some material and seen some third party videos [e.g. https://youtu.be/Ko5uj6wdftM] that seem to show the Endurance Lasers are actually achieving this . . . and in above video example achieving a 0.075mm x 0.075mm laser dot [albeit with the addition of a lens adapter/extender]
I would be very interested in any further opinions and/or input on this principle.
I am far from an optical engineer - i am the technical support guy that likes to know the bare minimums on things so i dont make a fool of myself . I often fail at the latter!
My views below are mine and do not represent an âofficialâ statement of any sort!! (just in case! LOL)
And yes your understanding is correct in theory, but in practice this methods of collimating lenses are not really what is used as i understand it. If you think on it, and assuming the more optical glass you put in between the material and the laser source, the more you lose in optical out, up to 30% per element, you realize is really not possible to do it as per theory. the math does not add up.
5W + 5W = 10W± / 30%obsorption = 7W. So you would need 3 sources of 5W, to get the final 10W.
Also it becomes extreamly dificult to aling everything in factory. A fully colimated 10W or 20W multi diode module would cost 1000s not 100s. Also all the glass to absorbe and survive 10W power, let alone 20W are not simple, let alone afordable.
So then two options are possible.
a) Ignoring glass assemlby costs for a moment. You over drive the diodes, to allow a ±10W optical output even with the aboroption of the glass elements, bad idea, very very bad idea
b) you make it simpler, more afoardable and allow the dot to be what it has to be. as you said 2:1 ratio
In the case of Ortur module, which i know best, the 2 modules are aligned onto a combining lense/Prism, and the resulting beam is collimated to shrink the Y axis as much as possible with a simple lense element. Less fancy, simpler, and with the assumptions no one will buy a 10W module expecting a 0.02 0.02mm dot size.
We have a simpler aproach to it, and i believe everyone else uses the same or a variation of the very same.
A interesting benefit of avoiding multiple groups of glass elements is the beam focal range is much longer too, allowing the better cut depths (which is the main goal of a 10 or 20W module really)
Now the downside of multiple diode modules, regardless of method, 1 rougher DHL or UPS driver and the diodes or the combining prism can be nudged just enough to set the whole aligment out of wack. Is very rare, maybe 1:1000 but i seen it happen.
. I often fail at the latter!