New new build

[absolom7691]

Ya reckon?
Isa reckon that the motley mess is more a matter of large beam diameter, rather than combining wavelengths.

I would say partly. I think the larger diameter plays a part, but I think several other factors are at play. Differing divergences and beam shapes are probably a huge one. None of the emitters match each other. Different fast axis and emitter sizes, even on single mode diodes. The fluctuations in collimation physics due to chromatic aberration, I'm sure the red focus mechanics are different than the green and blue. Hell, even an ever-so-slightly off center collimator changes the beam profile a lot. Getting diodes to match perfectly sounds like trying to align kyber crystals without using The Force. When moving up to multi-mode diodes, amplify that by 1000. Spatial filtering would probably help a lot. The polarization probably needs to match as well. How tightly, I wouldn't know but I'd guess within a fraction of a degree. Ions were so much easier!!! I miss my ALC 60x!!

[laserist]

my experience with diodes is the beams are too large for the optical effects I had dating back to Ions. But a positive lens near the effect that focused the beam(s) smaller where they passed through the effect did the trick. Having convergence/divergence didn't seem to matter. I doubt polarization is critical since:

Physicist Paul Dirac stated that each photon interferes only with itself and that two different photons never interfere. In quantum mechanics, a single photon's wave function passes through multiple paths (like both slits in a double-slit setup) and interferes with itself, meaning what interferes are probability amplitudes rather than distinct particles. - Google AI Overview

[absolom7691]

my experience with diodes is the beams are too large for the optical effects I had dating back to Ions. But a positive lens near the effect that focused the beam(s) smaller where they passed through the effect did the trick. Having convergence/divergence didn't seem to matter. I doubt polarization is critical since:

Physicist Paul Dirac stated that each photon interferes only with itself and that two different photons never interfere. In quantum mechanics, a single photon's wave function passes through multiple paths (like both slits in a double-slit setup) and interferes with itself, meaning what interferes are probability amplitudes rather than distinct particles. - Google AI Overview

For my build that's underway, I have had to play with the collimation a lot to get right focal point.

Actually yes, now that I think about it, polarization would probably only affect brightness but it's most likely negligible since any single brewster angle would be all but eliminated on an imperfect glass surface. Chromatic aberration would probably affect multiple stacked beams more than anything, since the refraction index of each wavelength through the glass is different. I have honestly never given this much thought before. Fascinating stuff. Thanks, guys!

[absolom7691]

Food for thought.
Discovered these yesterday. They're new ones on me, but look great! Does anyone else recognize how they're achieved? 🤔
Surface reflections off an aquarium?
No idea on this one.

If I were a betting man, I'd say two pieces of glass mounted on the same hub, the back piece (beam entry) is a somewhat complex pattern, the front one (beam exit) is a multiple "lens" type, like the Whittemore & Durgin "Hammered" pattern. I'd say the two pieces are an inch or more away from each other to let the pattern from the first glass realize. The second glass works similar to multiple lenses. At least, that's my theory. I could experiment a little.

W&D Hammered pattern:
20260812_084233.jpg


Edit.... it stretches at the edges, that means it's cylindrical. Could be a hobnail bowl. I'm going to play a little. lol

[absolom7691]

Wanted to ask whether you had though about adding a mylar burn wheel.
Searched YT for examples, but this is the closest I could find.

Both need to be properly mounted onto a slow rotating wheel with finely controlled intensity to bubble up with control, along the melting point.

I was thinking about it. I wasn't sure if I had enough power but I was able to get an anti-static bag to deform with just 100mW. It should be doable with the power I have!

[absolom7691]

but this is the closest I could find.

I found the video I was looking for... at the very end, the burn-through

[laserist]

Way back when Laser Images used a thick aluminized mylar (refered to as "green back") for the burn at the begining of laserium I. Which exploded covering the dome. The chopper was used to control the intensity for the effect because it was much more linear than the intensity control device. And used a thin mylar for burn effects in a thankfully short lived encore to The Pines of Rome that someone once said looked like fish bladders.

We also made standoffs and wheels using perforated aluminum dipped in lacquer and slowly rotated vertically while the lacquer set up to form an array of negative lenses.

[absolom7691]

Oh, so you already know about mylar burns.
Were you also a LII laserist?

Not a Laserium laserist, but I have experienced quite a few shows at Griffith. When I got my first argon laser, I experimented with all kinds of things, Pop Tart wrappers, crinkled foil and eventually found a mylar sheet that had adhesive on the back. That's when I discovered the burn-through. Years later, Gary Stadler was repairing an Omni 150P PSU for me and he showed me one of the projectors he had in his "garage". I don't know if it was a Laserium projector or an AVI, I only saw a glimpse of it and it was about 25 years ago. It had a burn wheel in it.

[buffo]

Gary Stadler was repairing an Omni 150P PSU for me and he showed me one of the projectors he had in his "garage".

Oh man... Gary Stadler... There's a name I haven't heard in a while. I bought my very first argon laser (a single line 488 nm air-cooled SP-161) from him back around 2000 or so. Years later I found out that he was the guy behind the Aurora power supply.

In my mind, Gary's biggest claim to fame is one that he never got official credit for. Turns out that he did the lissajous effect seen in Star Trek: The Motion Picture, when they first engage the warp engines and end up in a wormhole.

Gary told me they used an orange HeNe laser and a pair of AOMs to do the scanning (because regular mechanical scanners just weren't fast enough for the complex pattern). They only had something like 1 degree of scan angle out of the rig, but the resulting pattern was absolutely beautiful.

After the studio had finished filming the effect, they told Gary, "We can either pay you the contracted amount for the effect, or you can be listed in the movie credits..." Since the job paid something like $50,000, Gary and his partner wisely took the money.

Adam

[absolom7691]

Oh man... Gary Stadler... There's a name I haven't heard in a while.

He was something! That dude would just decide to do stuff. Glassblowing... sure. Design an argon PSU... sure. Build a 3ch G-120 amp... sure. Record music... Sure. Last I saw him, it was at his place in, I think, Fallbrook, near San Diego. I paid him for the PSU repair and he showed me around a little. As I was leaving, A singer showed up to do some vocals for the album he was cutting. Definitely a one of a kind person!