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Ultra low power lasers

allyn

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Oct 30, 2011
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Folks:

I am a light artists. I make jewelry that incorporates stainless steel, glass, quartz crystals and LED's.

I am looking for ulta low power lasers. I am talking about under 100 microwatts. That's microwatts, not milawatts.

I want to incorporate them into my jewelry and have them safe, similar to lasers in supermarket scanners.

Most sites I visit seem to have a bottom of about 1 millawatt. That is too much.

Thanks

Mark Allyn
Mark Allyn Artistic Journal
 





TuhOz

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Aug 23, 2011
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100 microwatts... arent that like 0.1mW?
Correct me if I am wrong.
What color (nm) are you looking for?
 

madog

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I don't think you will find anything below 1 milliwatt. Not sure though. I have not heard of a laser below that. If you are concerned about safety, anything below 5 milliwatts will be safe.

I looked through your journal and it looks like you have lots of fun.
 
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Believe it or not, you can actually under-drive a laser diode rated for 1 mw. Now, getting exact measurements of power while setting the current could be tricky as some of the better LPMs that people own around here will have a resolution of .1mw at best.

But yes, it could be done.

Though I'll warn you now, you will be limited on the number of colors to choose from.

For instance, green and yellow, orange and probably blue are out of the question.. so that leaves you with a slightly overpowered violet or a red.

If these laser will not be focused, and directed to a single point however, I can assure you that 1mw for some of the lesser visible wavelengths like red and violet should be sufficiently safe and visible.

100uW of 660nm or 405nm light is not very useful at all if you intend the light to been seen... at all.

1mw of undirected (scattered) laser light would be very safe- but still, it depends on your particular application from case to case.
 
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You can buy a 0.2mW yellow he-ne. :p
Or 1mW 405nm
 
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Would you even be able see it below 0.5mw?

and 1mw is only dangerous if you manage to point it in your eye at point blank range for 5+ minutes

you could get 1mw then block them out with something
 
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I think the best way to do this would be to take a 1mW, maybe even a 5mW laser and pass it through a filter to dim it down. Most laser diodes do not lase below ~1mW, so the filter may be the only course of action.
 

allyn

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Folks:

Sorry, I should have mentioned what specific position these laser diodes will have in my artwork . . .

I would have the laser aimed at the impurities of a quartz crystal and make it 'sparcke' with the characteristic 'sparke' of laser light.

I am *not* at all interested in making the beam itself visible in open space; ie; doing a 'laser show' from my necklace.

For example, I would have a quartz crystal illuminated with a diffuse red light from a red LED, but I would have a blue micro-laser aimed into the crystal at a specific spot in the imperfections within the crystal and have them 'glimmer' or sparkle among the gentle red background of the rest of the crystal.

Ideally, I would like to find low power lasers in as many colors as I can.

Another example would be to take a large qwartz crystal (say, about 3 inches long); light it with a diffuse deep violet led; and then aim red, blue, and green lasers at different spots in the imperfection within the crystal, so I can see glimmering red, blue, and green (due to the interference or diffraction).

Another approach would be to grind patterns into stainless steel using an angle grinder; lighting the entire piece of steel with one color and then aiming lasers of complimentary colors at different spots on the grinding.

For this purpose, I don't care about super accurate beam coherence or focus. What I
am looking for is the 'sparkle' effect of laser light.

Because I am aiming the light into a crystal or reflecting it off of ground metal, it will be going into your eyes.

That is why I want it to be as low power as possible.

I know that this forum is much about high power, but for this application, I need to head into the other direction.

Thank you

Truly,

Mark Allyn
 
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If it the light is diffusing off a surface then you could probably go up to 10mw without any problems.
 
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Get a few 5mW laser modules and use neutral density filters to attenuate the beam to an appropriate level.
As long as the laser beams are not aimed directly into the eyes of the viewers, you don't need to worry about safety. Diffuse laser light is not any more harmful than "regular" diffuse light - unless, of course, you are dealing with much higher power.

If your project(s) require light spread over a large area, LEDs will be simpler and cheaper to integrate.
 
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Folks:

Sorry, I should have mentioned what specific position these laser diodes will have in my artwork . . .

I would have the laser aimed at the impurities of a quartz crystal and make it 'sparcke' with the characteristic 'sparke' of laser light.

I am *not* at all interested in making the beam itself visible in open space; ie; doing a 'laser show' from my necklace.

For example, I would have a quartz crystal illuminated with a diffuse red light from a red LED, but I would have a blue micro-laser aimed into the crystal at a specific spot in the imperfections within the crystal and have them 'glimmer' or sparkle among the gentle red background of the rest of the crystal.

Ideally, I would like to find low power lasers in as many colors as I can.

Another example would be to take a large qwartz crystal (say, about 3 inches long); light it with a diffuse deep violet led; and then aim red, blue, and green lasers at different spots in the imperfection within the crystal, so I can see glimmering red, blue, and green (due to the interference or diffraction).

Another approach would be to grind patterns into stainless steel using an angle grinder; lighting the entire piece of steel with one color and then aiming lasers of complimentary colors at different spots on the grinding.

For this purpose, I don't care about super accurate beam coherence or focus. What I
am looking for is the 'sparkle' effect of laser light.

Because I am aiming the light into a crystal or reflecting it off of ground metal, it will be going into your eyes.

That is why I want it to be as low power as possible.

I know that this forum is much about high power, but for this application, I need to head into the other direction.

Thank you

Truly,

Mark Allyn

That sounds like it would look amazing. I hope you are able to figure out a solution, I'd love to see the results.
 
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Oct 4, 2011
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Go to Target and buy a cheap red cat toy laser. This will be about 1mW. Anything less will be effectively "unstunning" I think. Good luck finding blue for any cost low enough to be practical. Low power blue diodes are pretty expensive and not available in powers that low. Green becomes cumbersome. You should probably stick to LED's.
 
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Jun 21, 2010
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If you have room for driver electronics, you can always use a driver that can be modulated using PWM (pulse width modulation), and use 10% or 2% duty cycle waveform to drive a 1mW or 5mW laser to reduce the *apparent* brightness to 100uW. I emphasize *apparent* because the instantaneous brightness will still be the original power of the laser diode, so you must not use the PWM technique to make a laser of higher than 5mW *safe*, because they will not be safe. What you will be doing is only reducing the *average* power, and thus the brightness, but the instantaneous power will still be dangerous to your eyes.

PWM can easily be achieved using a simple as a 555 timer to "chop" the input voltage of a normal lower power laser pointer driver circuit. A web search for "555 PWM" should get you started.

Dan
 
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The main question here would be if you're going to make this portable as in a necklace or if it's going to be something for indoor decoration.
 
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If you're in need of low power lasers I recommend wickedlasers.com
Just to add: This here above is a fine example of sarcasm for those who know wicked lasers.

100uW is more than visible enough when it hits something, it almost looks like people consider 1mW the least amount of light that is still visible. Let me remind you: Class 2 is 1mW and below and is the absolute maximum exposure you could get in an accident in a proffesional situation. Class 2 is made to be safe if you have a proper blink reflex. So it's definately not the case that 1mW is not very visible. 100uW in a small dot is sitll quite bright.
In this application the scattered radiation is what is visible which requires somewhat higher power, but 100uW may not be a bad first guess, Although I'd go for 1mW because lowering power is easy, and the scattering may not be as strong as you expect.
 




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