power reduction with diffraction grating?

[makeitnew]

I've been trying to find a ratio for how much power is lost each time a laser is split. I was hoping it could drop mw output on a ~ 100mw laser through a star grating in order to use at concerts. if there are 100 dots would that mean each one would be 1mw?

 

[lasersbee]

I've been trying to find a ratio for how much power is lost each time a laser is split. I was hoping it could drop mw output on a ~ 100mw laser through a star grating in order to use at concerts. if there are 100 dots would that mean each one would be 1mw?

Simple answer.... NO...

A little research and the [Search] buttons would have easily
gotten you to this Thread...

http://laserpointerforums.com/f70/extend-lpm-range-filter-74207.html

It explains how you can reduce the beam power of a Laser


Jerry


You can contact us at any time on our Website: J.BAUER Electronics

 

[makeitnew]

ah cool thanks for the answer.

I'm afraid though even searching with everything I had I didn't find that page. I wasn't looking for the key words in that post. It's hard to know to search what you don't know to search, but again, thanks for explaining and linking.

The reductions in power seem less than significant for my thoughts. It's unfortunate that splitting the beam up doesn't proportionally divide power though.

how does that not break conservation of energy? Is it a phasing related reason?

 

[Bionic-Badger]

Are you really talking about reducing the beam power, or just wondering how much power each light-point a diffraction grating contains? It is possible each dot is only 1mW or less, but without actually metering it that may not be the case (such as higher power points near the center). I think most of those laser diffraction gratings shoot for even lower power per point.

 

[makeitnew]

Are you really talking about reducing the beam power, or just wondering how much power each light-point a diffraction grating contains? It is possible each dot is only 1mW or less, but without actually metering it that may not be the case (such as higher power points near the center). I think most of those laser diffraction gratings shoot for even lower power per point.

Yes I really want the power down, and since a diffraction grating looks cool, that's what I thought might be best.

So the spread doesn't happen evenly... that's not safe then. I found a diy lpm guide with black foil and a IR temperature meter. So perhaps i'll make one and buy some gratings, but i'd rather not wast money.

I wonder if I can just rip it apart and put in a smaller flex drive. Unfortunately there isn't much info for making a laser weaker. haha. Seems to be counter productive to most

 

[Bionic-Badger]

If you're using a green laser you really can't reduce the power with your own driver, but you might be able to pot mod it for reduced power. It might actually just be easier to buy a lower powered module, like a 30mW one. I think Lazerer.com has them for cheap. Even a 5mW green will look pretty bright, so you might try that and work up from there.

You can try the temperature sensor, but you need to calibrate it to a known source, otherwise you'll just be reading relative temperature measurements, not output power.

 

[makeitnew]

unfortunately it's 405 so it's almost invisible to me. I'm thinking if I can make it a cool fog machine laser and it won't blind people i'll be safe. I'm pretty sure it's 100mw now. maybe less. I foudn the same laser listed with 100mw and 1000m is what mine had listed for distance. so it has to be 100mw or less with bad advertising.

I'll check lazerer for those flex drives. thanks.

anybody have a safe mw rating and still make it worth doing? I've got one vote for 30. spread out that should be safe enough right?

 

[Bionic-Badger]

You might want to look into a different laser wavelength too. 405nm is cool, but you really do need higher powers of it to be very visible even with fog. Maybe you can work on just situating the laser so that it is further away from the audience, and therefore will spread

 

[hakzaw1]

I sent you a PM about your taking a laser to a concert idea-
these are NEVER welcome at concerts and even less at a laser show-
IMO there is no laser that is safe to shine in the faces of people- why would you even want to do that?

 

[makeitnew]

I WOULD NEVER SHINE A LASER IN SOMEBODIES FACE LET ALONE THE ARTIST i CAME TO SEE. OR A PLANE! GOT IT PEOPLE!

To everybody else.... thank you so much. you make some valid suggestions. I'm trying to get info on maybe using a neutral density filter but people are being uncooperative in helping.

 

[Bionic-Badger]

Well even if you've got good intentions, people get very wary when they see someone using a laser in close proximity to them. People may report you as an audience hazard.