Divergence

[Atomicrox]

After reading a bit about beam divergence I'm finding diode specs more and more strange.
Take this one for example - it lists typical divergence as 9º and 17º on horizontal and vertical axes.

This one is supposedly a single mode "good quality" beam and lists 7 and 20 degrees.

I thought good values of divergence were around 1 or 2 mrad.

Are those values for the diode without any optics? If so how do I know what is the "collimated" divergence of a diode other than buying and measuring?

 

[ElektroFreak]

Those figures are for raw diode output, no optics.

You can calculate what your end divergence will be if you know the details for all of the lenses used to collimate. In most cases it's good enough simply to distinguish between single-mode and multi-mode. Single-mode diodes will always have lower corrected divergence figures than multi-mode.

 

[Atomicrox]

Thanks! Can those values at least be used to compare beam quality or are they useless without defining the optics?

 

[ElektroFreak]

No, not useless at all actually. They represent the actual beam specs of the diode itself. If someone is trained in optics and understands lens calculations they can use these specs as a guide for what optics to use to get the beam specs they're looking for.

 

[joeyss]

Yea, but don't you need the emitter size and area for ideal calculations?

 

[ElektroFreak]

Sure do!

 

[Atomicrox]

I'll have to read more on optics then