Spatial Filtering Video

[polishedball]

The filter uses two optics. The other are for diode correction.

[planters]

I don't think so. The spatial filter can only filter at a focus and so unless you are willing to filter only one axis and use dual positive cylinder lenses rather than the more common negative followed by a positive, you will need a pair of PCX lenses. If you only use these then you will be unable to correct the highly asymmetrical stripe out of the diode. In the interests of compactness you could place the first positive so close to the second cylinder that it contacted it (don't glue as adjustment of the cylinder will be easier without the PCX in line). The result would seem something like three lenses.

[steve-o]

So no easy-cheezy then .. well, anyway, thanks for your well thought out and extremely cool vids, Planters .. very nice :] Cheerz ..
-- just have to ask .. who is the camera-man/woman -- ? -- They do a good job

[planters]

I think it is pretty easy, but that is just me. I know my projectors are larger than average and so the extra beam length is not a big deal. But, the quality of the beams! I have yet to see anything out there that equals them. With the G71 modules I get an average of 0.5mrad (full angle, Kavant!) through a 4.5 mm scanner aperture. I have to telescope the typical CN 532 DPSS up to the same 4.5mm limit just to reduce its divergence close to the red. I'm sure there are systems out there that surpass these beam parameters using ions or OPSL's, I just haven't seen them and of course they have their own issues such as 3 phase or $100,000 price tags.

The cameraman had a little battle with the auto-focus in the last video, but he does a good job. In this case, it was my older son who is the programming whiz. It helps a lot to have someone film who understands the subject matter because they can anticipate where the demonstration is going.

[LaserCo]

These are great video's Eric! you say it is one person with you, during these I was always wondering who was helping, at one point i see him (elbows/yellow shirt) across from you on the other side of your projector layout yet the view is as if someone is behind or beside you with a mirror and he is pointing the camera at the mirror then.

He is so lucky! I wish the hell my dad was like you

edit: too far off topic!, i put it back to pretty much the same as my original post, sorry

[mojo]

I uploaded a video to YouTube a couple of days ago that goes through the set up and benefits of spatial filtering

Your videos are great. There're not so many people out there sharing such helpful information. Thanks a lot!

-mo-

[dkumpula]

Thank you for making and posting this, Planters!

While you posting your latest video, I was making my own variation on your razor approach and wondering why masking didn't help without having spacial filters in place. With your clear explanation of what is happening within the beam, I now understand what is going on and how to deal with it.

I also Enjoyed the Modest Mouse in the intros and credits too.

-David

[CountFunkula]

Awesome video! It's great to see the spatial filter getting some love for "cool LOOKING things you can do with a laser" outside of holography!
You magnet+razor blade approach is a nice alternative to a delicate (and EXPEN$IVE) pinhole!

[SimonNeve]

just to be clear for the slow one here - if i have like you say 90 mm to play with and i use a 50 mm lens and a 35 mm lens i will end up using 85 mm of space and have a ratio of 1:1.43 witch will make my beam from "3x3" mm to 4.3 x 4.3 mm right?
and if i just want a 1:1 ratio i will take two 35mm lens's and then end up using 70 mm of space?

thanks!

[polishedball]

just to be clear for the slow one here - if i have like you say 90 mm to play with and i use a 50 mm lens and a 35 mm lens i will end up using 85 mm of space and have a ratio of 1:1.43 witch will make my beam from "3x3" mm to 4.3 x 4.3 mm right?
and if i just want a 1:1 ratio i will take two 35mm lens's and then end up using 70 mm of space?

thanks!

That's how it worked for me.