INSANE Dilda Divergence

[brando132]

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.

 

[laser_freak]

Wow that seems like impossibly good divergence. Looks nice

 

[aryntha]

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?

 

[HIMNL9]

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 )

 

[davidgdg]

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 .....

 

[brando132]

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 .....

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?

 

[Gryphon]

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

 

[realista]

also mine dilda has better than .5 mrad