Page 2 of 2 FirstFirst 12
Results 11 to 18 of 18

Thread: white 'n tight

  1. #11
    Join Date
    Feb 2005
    Location
    Florida
    Posts
    802

    Default

    Good question,...Ive never tried it,...seems possible..

    Still of course it still is not a laser obviuosly.
    And because it is not a coherent source it would never be able
    to be a straight line. Laws of physics thing..
    The beam is only as good as its source.
    So I dont think the fiber would help because when the light escapes out of
    the end of the fiber,.. it will spread again,,..Because it is a non-coherent beam.

    To have a coherent beam -
    It must have bombardment of photons from excited atoms/ions/molecules to the next in line ..
    a chain of bombardment sortaspeak.
    Also a pair of mirrors, one at each end of the laser forming a resonator ,
    which allow stimulated light to bounce back and forth through the lasing medium.
    Usually, one of the mirrors is totally reflective while the other is partially transparent to allow the laser beam to escape.
    This is what forms the coherent line..

    From what Ive read so far is what you will have is a smaller image of the emitter...
    But even if you could focus it down to a very small (sub millimeter) spot it would still spread!!!
    "My signature has been taken, so Insert another here"
    http://repairfaq.ece.drexel.edu/sam/laserfaq.htm
    *^_^* aka PhiloUHF

  2. #12
    Join Date
    Jun 2005
    Location
    SoCal
    Posts
    508

    Default

    Actually the perfect thing to use is one of those "Ednalights" which are the light
    pointers people used before they invented cheap laser pointerss. The rules of
    collimation pretty much guarantees that a collimated beam is going to be an
    half-inch or so in diameter from a standard LED using normal optics (no
    matter how much money you throw at it) and more practically about an inch or
    so... Thus it'd make for a fairly low power beam... Another thing to note is that
    the luxeons have even bigger dies so the beam profile is even worse there,

    Now the real beauty would be using one of those HID beams (maybe a
    projector bulb?) which pumps out 400-800W of power... you can afford to lose
    some power loss there... The projector bulbs have a very tight arc gap so
    you'd have some really tight beams (on par with those 40W Yags)

    The trick to making everything go is really just feeding as much power as you
    can into a fibrefeed, allowing you to collimate at the other end.

    One project which I never got started was building a flashlamp/strobe light
    collimator. I had the shell of an DMX intellibeam I was going to bounce it off of,
    but I kept feeling that I was doing a lot of work when I already had perfectly
    good lasers.

  3. #13
    Join Date
    Feb 2005
    Location
    Florida
    Posts
    802

    Default

    Yep , Good idea using HID or ARC

    I wonder how much light one could squeeze into a fibre?
    and be usable for white light?
    I guess it could be done for any color fundamentally.


    I guess one would have to have a "VERY BIG" light pipe!!

    But I can see that working somehow..

    *^_^*
    "My signature has been taken, so Insert another here"
    http://repairfaq.ece.drexel.edu/sam/laserfaq.htm
    *^_^* aka PhiloUHF

  4. #14
    Join Date
    Jun 2005
    Location
    SoCal
    Posts
    508

    Default

    Well I was keeping track of the Israeli scientists who were developing
    a "Sunlight powered pseudolaser" for surgery in 3rd world countries...





    http://dx.doi.org/10.1063/1.1510942

    Basically they had a sun tracking parabolic lens which focused sunlight
    (which is already perfectly collimated for all practical purposes due to
    the sheer distance) right into a fibrehead which was mounted at
    the focal point... They were able to get 5-20 usable Watts of surgery
    capable power for 5 hours a day out the other end!

    I have a bunch of photos and diagrams about it that I have somewhere,
    I'll have to dig them up...

    http://www.newscientist.com/article.ns?id=dn4009

    http://www.israel21c.org/bin/en.jsp?...y&enVersion=0&

    The original article with usable details is in Nature's pay for site,
    but here's an AP blurb:

    Associated Press -- Scientists in Israel have concentrated free sunlight into a
    high-intensity beam typically reserved for expensive laser surgery.

    Details of the liver surgery experiments on mice appear in Thursday's issue of
    the journal Nature.

    "It would be especially valuable in my university's medical center, which has
    not been able to afford a single laser fiber-optic surgical system," said the
    study's lead author, Jeffery M. Gordon of Ben-Gurion University in Tel Aviv.

    Sophisticated laser surgery equipment costs more than $100,000, while the
    sunlight scalpel system is assembled with off-the-shelf parts.

    Gordon and partner Daniel Feuermann used a rooftop mirror less than 8
    inches wide to focus bright sunlight and funnel it down a long optical fiber
    about 60 feet into the lab. Other mirrors manipulate and concentrate the
    sunlight along its journey.

    The beam can be adjusted, but photons cannot be stored in a battery like
    electricity. So the sunbeam scalpel is only useful when the sun is shining -
    bad news for hospitals in some cloudy or dark cities like Seattle or Stockholm.

    "Its key drawback is its being restricted to clear-sky periods in sunbelt
    regions," Gordon said.

    In the experiments, the researchers anesthetized two female rats. They
    directed the concentrated solar energy to lesions on their exposed livers that
    simulated cancerous tumors. Each animal was irradiated twice in separate
    sections of their livers.

    The surrounding, untreated portions of the rat livers functioned normally after
    surgery. Liver cells exposed to the sunbeam were vaporized in a pattern
    similar to liver surgery by laser, they reported.

    Gordon said the inexpensive system could be used in desert communities, as
    well as field clinics for the military and refugee camps.

    The sunlight scalpel would not be appropriate for more delicate laser
    procedures, such as surgery on the eyes and skin, which use a "cool" low-
    power beam.

  5. #15
    Join Date
    Jun 2005
    Location
    SoCal
    Posts
    508

    Default

    I had emailed the guy who did this research and he was very helpful and
    provided me a copy of his paper. I just need to find it...

    I found some more pictures online to whet your fancy.






  6. #16
    Join Date
    Feb 2005
    Location
    Florida
    Posts
    802

    Default

    WOW...very kewl''

    Now to mirror coat those big aluminum 10 foot dishes
    I got in my back yard ...hehe :twisted:

    Thanks Dude...

    *^_^*
    "My signature has been taken, so Insert another here"
    http://repairfaq.ece.drexel.edu/sam/laserfaq.htm
    *^_^* aka PhiloUHF

  7. #17
    Join Date
    Feb 2005
    Location
    Florida
    Posts
    159

    Default

    Yay!!

    Now got something new to look forward to....

    Thanx, yaddatrance!!!
    Responses always welcome...whether intelligent replies or smart answers

  8. #18
    Join Date
    Jan 2007
    Location
    Florida
    Posts
    4,382

    Default

    5-20 WATTS?? Wow! you could pipe that into a dark room or planetarium and...

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •