INSANE Dilda Divergence

So I was using my HeNe in my backyard and thought I'd get my dilda to compare colors, so I set it down focused it to the same size as my HeNe, but bumped it on the way up which set it perfectly back to infinity. I'm talking .12mRad-like infinity!

Here is a picture of the dot at around 17 Meters it's a hair over 7mm.(my sis's ruler not mine!)



The dot is messy because I wrecked my lens burning a match.

At aperture the beam is exactly 5mm.

Using pseudonomen divergence calculator with that data I got 0.12352941113637285mRad

These are shots about 2/3 down the beam. It's quite thin.(me likes)





And this is standing next to the dot, my camera puts the point of view a few meters in front of the camera, so I am farther then it looks in the picture.

Wow that seems like impossibly good divergence. Looks nice

well. damn - the only thing is, that may not be true 0.12 mrad divergence, as you may have just moved the beam waist out to a far distance? (I think...) Someone can correct me if I'm wrong... but isn't divergence limited by the emission and the diode, and not the optics?

Divergence is due also from the potics (except if you talk about natural, unfocused divergence of th laser diode chip) ..... and cause is a relative measure (calculated from the interaction of 2 different measures, not measured directly), it can be, theorically, also 0 (if you get an optic that produces a perfectly parallel beam, that have the same diameter in any point, this is divergence 0)

Ofcourse, there is always some diffraction and refraction, in real lenses, so 0 is virtually impossible to obtain in practical field ..... but can be obtained some very good results (take in consideration beam expanders, as example )

To be sure, can you get some measurements every (say) 1 metre from the aperture? If you are showing 5, 5.1, 5.2 etc then you really do have .1 mrad divergence!!

OTOH, if you intially get a reducing width, then it's what Aryntha says. Would be interested to know. I don't use my Dilda much, but if it can produce 0.1mrad then i'll charge her up .....

davidgdg said:

To be sure, can you get some measurements every (say) 1 metre from the aperture? If you are showing 5, 5.1, 5.2 etc then you really do have .1 mrad divergence!!

OTOH, if you intially get a reducing width, then it's what Aryntha says. Would be interested to know. I don't use my Dilda much, but if it can produce 0.1mrad then i'll charge her up .....

Click to expand...

I just tried it again and measured the dot just a hair under 7mm, and a wlak along the beam with a DVD case and not once did the beam converge into a point! I'm loving this thing, and am gonna have to get a new one. Anyone know anything about the waterproof o-like's focus?

^ Thats amazing, so then you truely have great divergence, now just add a dab a super glue so you don't loose the focus

also mine dilda has better than .5 mrad