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Collumating non coherrent light (*topic changed*)

daguin

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Re: coherent light

Foobario said:
[quote author=keeperx link=1221369956/0#10 date=1221480963]ok what about sticking a crapload of bright ass LEDs in a box and fiber coupling. then trying to collminate the fiber output.
It depends... metric crapload, or imperial?
[/quote]


"Crapload" is obviously an avoirdupois unit of measure

Peace,
dave
 

Switch

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Re: non coherent beam (*topic changed*)

What about brightass? :D

Anyway, about "collmination", you almost got it right. ::)
 

Ace82

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Re: non coherent beam (*topic changed*)

You could use some super bright LED's, and optics to collimate the light from all the leds to one point then use a beam expander and get a pretty nice beam, only you will need more power then the typical laser, and the beam will have to be 1 1/2" + thick, and it will loose most if not all its' brightness at ~50' - 100' and will still have a huge divergence and you would probably get equal to 1mW of light when comparing to a typical laser. This would be equal to a bunch of people dancing at a rave all on the same E trip completely feeling each other and moving to the same beat (organized chaos) compared to soldiers marching in a straight line. ;D Well besides Daguin’s altered anylogy, I know because I’ve tried this before. I did it in my back yard (which is aprox 150’) and I set it on one side and walked with the beam on my hand noticing that the divergence was surprisingly good, only the brightness decreased allot as I continued to the other side. It started off at about 1” and was about 2” at 150’ away but you could barley see it even up close in the night at that distance.
 

Switch

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Re: non coherent beam (*topic changed*)

You could use some super bright LED's, and optics to collimate the light from all the leds to one point then use a beam expander and get a pretty nice beam,
Well , I mean, If you're gonna try this, you're best bet is to use only 1 LED, as more will just add to the incoherence.Besides, you can't shine multiple beams into one spot entering some optics at different angles and expect them all to come out the same spot and in the same direction.No matter how many mirrors, lenses ,prisms or fiber optics you have, you simply cannot combine two beams relying solely on reflection and refraction. :-/ I'm pretty sure it's imposible. I mean, light doesn't work like water through pipes and hoses you know. ::)
 

Cyparagon

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Re: non coherent beam (*topic changed*)

keeperx said:
could i get a similar output as a laser?
No, similar output to an LED

keeperx said:
ok so culminating an led... can you get a "beam"
Yes, about the size and quality of a flashlight beam.

Switch said:
the prism idea still wont give you monochromatic light
That is contingent upon the light source. Compact florescent bulbs for example have very few lines:



especially in caparison with solar radiation :cool:

 

Ace82

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Re: non coherent beam (*topic changed*)

Switch said:
You could use some super bright LED's, and optics to collimate the light from all the leds to one point then use a beam expander and get a pretty nice beam,
Well , I mean, If you're gonna try this, you're best bet is to use only 1 LED, as more will just add to the incoherence.Besides, you can't shine multiple beams into one spot entering some optics at different angles and expect them all to come out the same spot and in the same direction.No matter how many mirrors, lenses ,prisms or fiber optics you have, you simply cannot combine two beams relying solely on reflection and refraction. :-/ I'm pretty sure it's imposible. I mean, light doesn't work like water through pipes and hoses you know. ::)
Actually, I did this using 5 leds and yeah, lots of the light gets blocked but the leds power defiantly adds up. And the "dot" wasn't perfect, you could easily see the distortion of the multiple led's. I guess it would be better to just use one of the large super bright led's now (I made mine 10 years ago) but this topic is crazy anyway and won't work up to anybody's expatiations anyway so :-X
 

Switch

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Re: non coherent beam (*topic changed*)

Well yea, I mean, if I try to focus one of those 9 led flashlights with a lens on the wall I get 9 nice and round dots. :-/
 

keeperx

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Re: non coherent beam (*topic changed*)

well my expectation is not to end up with an LED laser, but rather a nice LED beam (nice for an LED)

the thinking is this.. LEDs are bright and if one could harness the power in a collimated beam that was reasonably visible (even over a short distance) you could create a nice effect for use in accenting a laser show.

And it (this thread) has been highly educational for me.

Thanks :)
 

Ace82

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Re: non coherent beam (*topic changed*)

keeperx said:
well my expectation is not to end up with an LED laser, but rather a nice LED beam (nice for an LED)

the thinking is this.. LEDs are bright and if one could harness the power in a collimated beam that was reasonably visible (even over a short distance) you could create a nice effect for use in accenting a laser show.

And it (this thread) has been highly educational for me.

Thanks :)
Well sure it would work as you say for short distance, but it will NEVER have the nice laser effect with out the coherence.  It will probably look really cool and you could use all different colors, so you should think of the advantages of using the incoherent light for such, like a color filter wheel for changing colors or something like that.  You could get it focused pretty good, but there will be too much "spread" that will make the effect not look nearly as cool as a laser because the "spread" from a laser is mostly the reflection of the dot hitting the wall, not the light projecting from the source (unless your laser's lens is dirty).  
 

keeperx

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Re: Collumating non coherrent light (*topic change

Kent: My condolences on your meltdown, Knight.
Chris Knight: What meltdown, Kent?
Kent: I'm not saying you had one, because how would I know? But just in case you do.
Chris Knight: You slime!
Kent: It's your own fault, Knight. Didn't anyone ever tell you to make sure your optics are clean?
 

Ace82

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Re: Collumating non coherrent light (*topic change

keeperx said:
Kent: My condolences on your meltdown, Knight.
Chris Knight: What meltdown, Kent?
Kent: I'm not saying you had one, because how would I know? But just in case you do.
Chris Knight: You slime!
Kent: It's your own fault, Knight. Didn't anyone ever tell you to make sure your optics are clean?
:-?

Anyway, I was browsing PL and came across this: http://www.photonlexicon.com/forums/forumdisplay.php?f=28 you might find some cool info regarding this topic there.
 

Cyparagon

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Re: Collumating non coherrent light (*topic change

keeperx said:
well my expectation is not to end up with an LED laser, but rather a nice LED beam (nice for an LED)
Most already incorporate a shape in the epoxy enclosure to facilitate a smaller divergence. For those that don't. a hyperbolic reflector is your best option



Either way, this is about the best "beam" you'll get:

 

keeperx

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Re: Collumating non coherrent light (*topic change

ok what about a fresnel lens, would that change anything??
 

Switch

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Re: Collumating non coherrent light (*topic change

keeperx said:
ok what about a fresnel lens, would that change anything??
A fresnel lens does exactly what a normal lens does, only much worse, but it's way thinner. :p
 

keeperx

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Re: Collumating non coherrent light (*topic change

if thats the case.. why do lighthouses use them?
 

GooeyGus

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Re: Collumating non coherrent light (*topic change

because they require a huge lens... and conventional lens that size would just be ridiculous.
 




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