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Thread: DIY Machida grating?

  1. #1
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    Default DIY Machida grating?

    After seeing Buffo's grating pictures, I want a Machida grating!

    Unfortunately, the prices they're going for from "normal" vendors are insane.

    Wouldn't it be possible to take some single-mode fibers and lay them side by side to create a Machida grating?

  2. #2
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    Default Home-built machida grating ideas

    I would think so... Truthfully the one I have looks very simple, and was probably made exactly as you describe. I imagine you could use some *really* fine wire as well. Just lay several lengths really close together!

    Maybe you could do it in reverse... Apply some black paint to a glass slide and then cut slits in the paint with a razor blade? Don't know if you could get the slits close enough though... (The farther apart they are, the narrower the "fan" of beams will be.)

    Check with CTR Surplus... They had a CRAPLOAD of these things on E-bay a few years ago, complete with a heavy, solid aluminum mount and a rotating central optic with a toothed arm that locked it in place with the help of a solenoid. They sold the whole contraption for just 5 bucks, and they didn't sell well at all... (I think noone knew what they were!)

    Adam

  3. #3
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    Default

    I cant find the picture im looking for...

    It was a picture of the machida filter under an electron microscope.

    The pathways were varied in size but none of them were over 7micron wide. The real trick is how they make the thing fan out almost 180 degrees.

    The smallest fiber i know of is 65 micron so that would make a rather "sloppy" effect that basically decollimates the laser.

    Ill see if i can find that image and a source for the filters.

  4. #4
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    Just called CTR:

    They dont have any more.

    To quote the guy on the phone "Thats the surplus business for ya"

    Damn.

  5. #5
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    Default

    So I've been wondering about Machidas too for a while ... I did a little web research ... finally that degree in Japanese Language and Literature is paying off ... Download the Japanese font pack and check out this page from the "Machida Endoscope" site (yes they make endoscopes, like for looking down your throat or other various places on your body that can be looked into/down/up): http://www.machida-eds.co.jp/fdg.html - don't know if this is "the" Machida, but they do have diffraction gratings - no purchasing info though, but I can email them if anyone's interested? Let me know.

    ... And I quote (translated of course, starting from right under the pictures):
    Single Type Cross Type (the picture captions)

    Features:

    When making a diffraction pattern, multiple grooved slit difraction gratings are typical. A Fiber Grating uses fiber optic in place of the grooves to create cylindrical lenses, laid next to each other in a sheet to form a transmissive diffraction grating. Unlike the slit type diffraction grating, the loss of the incidence light is extremely small; almost all of the light being transmitted. When the laser is exposed perpendicular to the sheet, a diffraction pattern results from the interference of light.

    -Excellent transmission, yet wide field of view.
    -Possible to obtain a bright, distinctive diffraction pattern.
    -Possible to use a high power laser.

    Uses:
    -Every kind of measurement
    -Display
    -Laser marking
    -Position sensor

    Technical Specification:
    Model
    Dimensions (Diameter×Thickness)
    Fiber Diameter
    Fiber Count
    Type [it goes "single, cross, single, cross" - the next row goes "single, cross" ]

    Output Beam Angle: [ lambda symbol is wavelength ]
    laser type: [this goes "he-ne, argon, argon" ]
    ... looks like they are using 20/25/50 micrometer fibers, 100/200 per grating ... if you could get ahold of some optical cement, you might be able to make something like this on top of a microscope slide cover or something like that ... if you could find small enough fiber ...

    -Josh

  6. #6
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  7. #7
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    Default

    Contacted the people(i think) at: http://www.machidascope.com/

    Lets see where this goes.

    Though: getting our own fibers looks to be more promising.

    I always thought they sliced thin section from a bundle of different size fibers, never guess the horizontal attachment method...

    Surely simplifies the creation of these things at home.

  8. #8
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    Default

    Well, I have access to a binocular microscope at work... Great resolution down to well below a tenth of a micron. Of course, positioning anything at that magnification is going to be quite a challenge!

    Adam

  9. #9
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    Don't sneeze!

  10. #10
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    Default

    wow, why am I not surprised there is another Machida company ... actually it's a pretty common Japanese last name ...

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