Spatial Filtering Video

[polishedball]

Thanks so much for the push to try this, pretty amazed. i think i need higher quality blades, but for now very happy

The optics for the filter i built take up 90mm end to end including foot mounts. so not much space, the improvements are dramatic. see pics below of same comparison, then the best beam i was able to achieve after lengthen the beam distance. I seem to get some weird reflection off the blade as i can walk the wings out but they seam slightly replaced with a very faint ripple pattern.

[planters]

I found the best blades were a pack of 50 (so I'm set) @ $7 from McMaster-Carr. But, you might be a little off focus because even when I play with a machinist's rule as the blade, if the position is right it works very nearly as well. Try well past focus and iteratively slide the blade in and out of the beam as you slowly bring the mount in. You might even find a non magnetic aluminum strip that is free from any magnetic hold down force to the mount lets you find the sweet spot quicker. Look for the edge details in the blade/strip. When it is close to best they really are sharp.

Oh, and I forgot. You can toe-in the mount's feet toward the filter to shorten the length.

[polishedball]

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Oh, and I forgot. You can toe-in the mount's feet toward the filter to shorten the length.

Thanks ill check it out could be the case, also on the mounts I kept them foot out on this first build to be sure I had the most room between them to slide around the pin hole. Not that I have the spacing I'm sure ill shorten it up on the blue build

[slicklasers]

Great video, Thanks for sharing!

[absolom7691]

Thanks ill check it out could be the case, also on the mounts I kept them foot out on this first build to be sure I had the most room between them to slide around the pin hole. Not that I have the spacing I'm sure ill shorten it up on the blue build

What's the size of your module now? Judging from the pictures it looks to be 10"~12".

[kecked]

how about making these as a kit for use optics noobs

[polishedball]

What's the size of your module now? Judging from the pictures it looks to be 10"~12".

3.75x8 and if you look close you can see where the board is dimpled for cube, wave plate n PBS to double it up.

[kecked]

would this be possible with two microscope objectives and a few razor blades?

[planters]

The reason I did the video and used hand adjusted optics was to show just how easy and forgiving the technique really is. I think the problem with a module is that each projector is going to be a little different as far as available space, beam height and access.

I would go about this by determining where I have the most space and which laser(s) I want to filter. Decide what I want to do to the beam dimensions (bigger vs. smaller). With the ratio determined, lets just say this is "I can benefit with a 50% increase in beam size", then the ratio of FLs should be 1:1.5. Now, if I have say 90mm of space pick the closest available lenses that sum to no more than 90mm lets say a 50mm and a 35mm. Finally, place the 35mm first follow it with a 50mm and place the filter between these.

Because the first lens is in a nearly collimated beam, don't waste any space making this lens adjustable forward/backward. The video shows the simple lens mounts I make with the over-sized lateral mounting hole. These work a lot better than the typical "L" bracket in space limited applications.

I think microscope objective are a little overkill with their high order correction and if of very short FL then the size and positioning tolerances become very small.

[steve-o]

I just had time to skim this thread (nice vid Eric) and was wondering can this be done effectively with 2 correction optics instead of 4, like in your vid ?