Post your random pics!

[Gabe]

How cool is that !
I used to collect them as well, had a nice big variety of samples.
Passed them on to my sons too.

:yh:

I used to collect as well! Didn't do much hounding just buying and being in lapidary clubs. Looks like I'm young enough to still have my collection I may sell some of them though, I have at least a few grand that I could sell and put towards a mean laser, some camera equipment that I'd love, or dare I say.... put it in a savings account.... eugh.

 

[diachi]

Fiber coupled Argon as best I can tell:

Some argon pumped dye lasers:

And these beautiful 12W RGB modules from Aten Laser:

 

[CurtisOliver]

Beautiful images of lasers I must say. Love that rgb.

 

[diachi]

Beautiful images of lasers I must say. Love that rgb.

Yeah, I was really impressed with that RGB, great looking build quality, very neat, well thought out.

It's smart too - he's using achromatic lenses to spatially filter R, G and B all at the same time instead of individually.

 

[CurtisOliver]

That's a smart system. I want one.

 

[diachi]

That's a smart system. I want one.

Likewise, the price is a little outside my budget of $0 though...

 

[Cyparagon]

Weird how they chose to use 3 successive X-axis expansion stages on the red.

 

[diachi]

Weird how they chose to use 3 successive X-axis expansion stages on the red.

I'm not seeing it ... I see two cylindrical lenses for the X-axis correction and then two anamorphics for for Y-axis correction - which makes sense if you're trying to match diameter/divergence with the blue/greens.

Then there's the achromatic lenses for the telescope/spatial filter - which don't look like they're doing much in the way of expanding the beam, seems like it's more just for the sake of spatial filtering.

 

[paul1598419]

I'm not seeing it ... I see two cylindrical lenses for the X-axis correction and then two anamorphics for for Y-axis correction - which makes sense if you're trying to match diameter/divergence with the blue/greens.

Then there's the achromatic lenses for the telescope/spatial filter - which don't look like they're doing much in the way of expanding the beam, seems like it's more just for the sake of spatial filtering.

That spatial filter looks very much like every other one I've seen. I don't see it doing more than that. These are used a lot in holography, where i have my experience with them.

 

[diachi]

That spatial filter looks very much like every other one I've seen. I don't see it doing more than that. These are used a lot in holography, where i have my experience with them.

Yep, exactly, just doing regular spatial filtering, except with RGB instead of one wavelength.

Only difference really is that it's a proper pinhole with an adjustable mount rather than some razor blades and magnets...

 

[paul1598419]

Yep, exactly, just doing regular spatial filtering, except with RGB instead of one wavelength.

Only difference really is that it's a proper pinhole with an adjustable mount rather than some razor blades and magnets...

Every one I've ever seen is a proper pinhole of specific size and adjustable in three axes with usually a microscope objective lens. Never really saw a razor blade one, though I have seen a text that had a do-it-yourself spatial filter using an aluminum foil pinhole with a convex lens.

 

[diachi]

Every one I've ever seen is a proper pinhole of specific size and adjustable in three axes with usually a microscope objective lens.

A bunch of the DIY builds I've seen are using razor blades and magnets (Which work just fine) or home made pinholes and magnets, which also work just fine.

Best way to do it of course is with a proper pinhole and adjustable mounts. Just not as cheap.

 

[Cyparagon]

I'm not seeing it ... I see two cylindrical lenses for the X-axis correction and then two anamorphics for for Y-axis correction

All three of these are clearly X-axis. The prisms would have to be 90 degrees rotated along the beam axis to affect the Y axis instead.

The Y axis size is chosen by the collimating lens (with the X axis size being a function of this and dependent on the emitter shape). If you wanted a different Y size, you'd chose a different collimating lens, not add a bunch of optics elsewhere.

The only reason two prisms are used instead of one, is to preserve beam direction. One works just as well (if not better) otherwise. In my projector, I use just one, and have the red at a funny angle.

 

[diachi]

All three of these are clearly X-axis. The prisms would have to be 90 degrees rotated along the beam axis to affect the Y axis instead.

The only reason two prisms are used instead of one, is to preserve beam direction. One works just as well (if not better) otherwise.

I'm not seeing that ... The two cylindrical lenses are correcting the X, or horizontal axis. The prism pair is correcting the Y, or vertical axis - they (the prisms) are quite clearly rotated 90 degrees to be on their side, refracting the beam (and thus correcting it) on the vertical axis. The achromatic lenses are focusing both axes (but seemingly doing no correction on their own, other than creating a focal point at the pin hole) as they are either spherical or aspherical.
Am I missing something?

 

[Cyparagon]

No, I retract that. You're correct. The prisms are expanding Y for the red, but not the others.

The weird photo angles and glare got me turned around. My second point still stands:

Increasing Y size would not only be easier and cheaper using a different collimating lens to begin with, it would also increase X size, lessening or eliminating the need for X axis expansion.

If they were using the prisms backwards (hard to tell the angle here) to constrict Y instead of expand it, it would still be easier and cheaper to use a different collimating lens and simply expand X more. Best guess is they could only find one size of cylinder lens... or they wanted to use the same collimating lenses everywhere to keep BOM/sources low. I still would have done it differently.

 

[diachi]

No, I retract that. You're correct. The prisms are expanding Y for the red, but not the others.

The weird photo angles and glare got me turned around. My second point still stands:

Increasing Y size would not only be easier and cheaper using a different collimating lens to begin with, it would also increase X size, lessening or eliminating the need for X axis expansion.

Yeah, it certainly is a little difficult to see clearly in those photos.

Not sure why they've done it either - perhaps they wanted to use the same collimation optics for everything or couldn't find the correct optic to do the job the way you suggest. Seeing that they used two stages it suggests they needed/wanted different amounts of expansion on each axis for whatever reason. Only reason I can see for doing that is to match the red as best as possible with the green/blue which I'm assuming had similar characteristics on both axes to each other from the start, differing from the red.

To be fair ... the guy that makes these is on PL - he'd probably explain the reasoning here if either of us asked, perhaps he's already explained it somewhere over there.