Laser through fibers

I am thinking about constructing a Laser Suit or shining lasers 'from inside a body' (I design laser products for magicians and performers)
with this technique: one laser source on the back of the suit, with fiber cables running from them inside the suit or under a second skin (fake skin applied over real skin containing the wires)

My only problem is: "focus"
The laserlight conducts very well inside the fibers (an experiment with 200mW green showed it was still able to burn after 5m of cable) only problem is that focus is lost (the beam isnt focussed anymore to a tight beam)

Anybody has an idea how to focus the light to a beam again, I would need very small lens systems (as I would like to have it as small as possible, so the illusion stays even at close distance) anybody knows where to buy these?

ideas said:

I am thinking about constructing a Laser Suit or shining lasers 'from inside a body' (I design laser products for magicians and performers)
with this technique: one laser source on the back of the suit, with fiber cables running from them inside the suit or under a second skin (fake skin applied over real skin containing the wires)

My only problem is: "focus"
The laserlight conducts very well inside the fibers (an experiment with 200mW green showed it was still able to burn after 5m of cable) only problem is that focus is lost (the beam isnt focussed anymore to a tight beam)

Anybody has an idea how to focus the light to a beam again, I would need very small lens systems (as I would like to have it as small as possible, so the illusion stays even at close distance) anybody knows where to buy these?

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Very interesting idea. The issue with it as far as I see is that you will not be able to collimate the beam coming out of the fiber. You will need a focusing lens for each one and then to get any sort of decent beam you will need a small core fiber which will increase cost and make the losses inserting the beam into the fiber very high.

What I would reccomend is this, use small diode lasers and then embed them in the same material you would use for the fibers. http://cgi.ebay.com/50-pieces-650nm...34.c0.m14.l1262&_trkparms=|301:1|293:2|294:30 is a good example of the kinds of modules you would want and they will be cheaper then the alternative fiber approach.

Thanx for your input.

Problem is that those modules are to big for our new project + we would need at least 100mW green or 30mW blue per beam.
We performed already with our prototype lasers (Theo Dari, Laserman, D Retes productions,..) and 50 to 80mw with a small custom made beamexpander is ok for live performances (where you can make a lot of haze), but for TV shows we need at least 100to 150mW to get a decent beam (haze is limited for the recording process, also when moving faster you need higher power to get the same visibility,..)
Cost isn't so much an issue (price for 5x 100mw green diode or 5x 30mw blue on each finger for example is a lot higher than one high power laser + optics, even if they are expensive). We have already a lot of fiber optics used for illumiation in gastroscopy and colonoscopy cables, its the focussing thats a real problem.
I am now looking towards the companies that make those endoscopy lenses to put on fiber scopes, only problem is that medical material is sooo expensive.

ideas said:

Thanx for your input.

Problem is that those modules are to big for our new project + we would need at least 100mW green or 30mW blue per beam.
We performed already with our prototype lasers (Theo Dari, Laserman, D Retes productions,..) and 50 to 80mw with a small custom made beamexpander is ok for live performances (where you can make a lot of haze), but for TV shows we need at least 100to 150mW to get a decent beam (haze is limited for the recording process, also when moving faster you need higher power to get the same visibility,..)
Cost isn't so much an issue (price for 5x 100mw green diode or 5x 30mw blue on each finger for example is a lot higher than one high power laser + optics, even if they are expensive). We have already a lot of fiber optics used for illumiation in gastroscopy and colonoscopy cables, its the focussing thats a real problem.
I am now looking towards the companies that make those endoscopy lenses to put on fiber scopes, only problem is that medical material is sooo expensive.

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The problem you will have is one of the fundamental properties when dealing with light. Brightness is conserved or lost. It cannot be increased. Thus, if you put your light in a fiber, the beam coming out will be worse then the input. If you need to get a ton of beams out. You will need a ton of input.

I hate to say it, but if you are worried about he cost of a single medical fiber, you are going to be sorely disappointed when you find the cost of the blue and green lasers you need to get the power out you want and the cost of the fiber collimator. At that point. It may be worth it to hire someone to do special effects to put it in if you are looking at a TV show.

Hi,

I dont need an increase in brightness, my goal was to mount a 1 w green module on the back and distributing the brightness through fibers to +- 10 exit points, like that every fiber cable (every cable consisting of ++++ fibers) would have at least +-80mw output.

The cost of the fiber is no problem, it aint cheap but is acceptable, it are the needed lenses that are the problem:
every output needs a lens, I can buy these lenses (they are only 2mm in diameter so ideal for this project) from a medical company but they charge 450$ per lens so I am looking for small lenses at a better price.

ps lol at the remark of special effects: we ARE the people hired to do the special effects the whole Laserman concept (everybody knows it from the most popular performer: Theo Dari cf youtube) was created by our group. Till now we used modules mounted in the palm of the performers hand, but we want to go smaller and closer to the public with the illusion.

wow, surely like to know more about what you did and where this current project will go to!
you wrote that at the moment, the beam exiting the fiber isnt good enough. what does the end of your fiber look like? i guess its just the bare fiber with no additional optics after that? normally, from a flat fiber end, the light would diverge so fast as from a flashlight or the original laserdiode without collimator. you already burned things with the fiber`s beam? i guess only when touching what you burn with the fiber?
with a single collimating lens after the fiber, you can focus it to a beam/dot as small as the fiber (core). problem is the mounting.. you need some precise adjusting in distance between fiber and lens. you need some distance to begin with, so a regular lens will perhaps be too large no matter what.
my idea: GRIN-lenses. quite complex stuff, you should read the wikipedia-article for a start. basically its a cylindrical piece of glass, both sides flat. it focusses just like a regular lens. great advantage for you is, they can be custom-made for any "focus-distance". you can get the right one, fitting for the divergence of what exits your fiber. you then glue (optical glue!) the lens directly onto the flat end of the fiber. such a lens should be only a few mm long and transparent. if this is still too large (smaller wont be possible anyway), you could reflect the beam 90° with a turning mirror. you could even get some custom-made optics made: GRIN lens the diameter of the fiber with the right length (tunes the focussing), at the other end of the lens a 90° prism. this "head" would be a few mm long, the beam would exit 90°, so you would only need a tiny hole of the diameter of the beam in the fake skin. without that, you would have problems with the minimum allowed bending-radius of the fiber.
bare GRIN lenses go for a few $. custom-made ones wouldnt be much more if you buy a whole lot. lot means one "cycle" in production, which is several hundreds. sure, way too many for you, but still less expensive than your original "plan". you could combine your lenses and prisms by yourself with optical uv-curing adhesive, norland is what you need to ask google ;-)
what else.. fibers are pretty thin (the core, at least). someone needs to calculate through this, what happens when you focus your 0.1mm fibercore directly with a GRIN. a .1mm laserbeam is no option, for various (potentially deadly) reasons ;-)

uhm.. pics!

manuel

ideas said:

I can buy these lenses (they are only 2mm in diameter so ideal for this project) from a medical company but they charge 450$ per lens so I am looking for small lenses at a better price.

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You can harvest the output lens from a laser sled assy. Lens is about 4 mm diameter, about 1 or 2 mm F.L. You get 3 for $2 with free shipping.
http://hightechdealz.com/index.php?main_page=product_info&cPath=4&products_id=16
I recommend you buy just one set and test your idea first...

thats a good idea! for blu-ray (or hd-dvd) sleds, the fl is 0.8mm. you still need to attach it somehow. but then i dont think a custom-made adaptor at 10$ a piece would blow your wallet ;-)

manuel

oh, and welcome on LPF, feldspar!
enjoy your stay!
..and seems like you know your stuff, a well-informed and helpful first post, nice!

manuel

Revealed...

ideas said:

Till now we used modules mounted in the palm of the performers hand.

So thats how they did it

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