1mw Laser Pointer Question.

Renato1 (Renato) · #1 12-09-2014, 08:33 PM

If I get 5 or 10 legal 1mW laser pointers, and then bunch them with rubber bands and turn them on, visually, would they have nearly as much Oomph as individual 5mW and 10mW laser pointers?

Or would I just have the effect of 5 or 10 dud 1 mW laser pointers?
Regards,
Renato

RB (Andrew) · #2 12-09-2014, 09:29 PM

Not practical doing it like that, ie: to get the dots to line up.
You need to combine the beams using a beam combiner.
In theory though the dot will look brighter.

This is just hypothetical though, right?

Renato1 (Renato) · #3 12-09-2014, 09:39 PM

Quote:

Originally Posted by RB

Not practical doing it like that, ie: to get the dots to line up.
You need to combine the beams using a beam combiner.
In theory though the dot will look brighter.

This is just hypothetical though, right?

Thanks, but no - not theoretical. I was hoping to get nice multiple beams bright enough so that when I've aimed them at a bright DSO in the sky, people can follow them with their binoculars and go straight to the DSO.

And not have any reason for police to hassle me.
Cheers,
Renato

RB (Andrew) · #4 12-09-2014, 09:43 PM

What you'll end up with is multiple parallel beams though.
Granted they'll be close together but not close enough to be one coherent beam.

Renato1 (Renato) · #5 12-09-2014, 09:47 PM

Quote:

Originally Posted by RB

What you'll end up with is multiple parallel beams though.
Granted they'll be close together but not close enough to be one coherent beam.

Hopefully, near enough would be good enough, though they would peter out at a lower height than a 5mW or 10mW laser would.

I've ordered two as a result of another thread, I was just wondering if I should see if two are better than one - or take a punt and go and buy another three.
Cheers,
Renato

RB (Andrew) · #6 12-09-2014, 09:50 PM

Ok goodluck.

jenchris (Jennifer) · #7 12-09-2014, 09:51 PM

I point my scope by shining the laser down my ep hole the beam is amazing and I dont need a sighting scope.
I expect doing two at once may combine them.

Renato1 (Renato) · #8 12-09-2014, 09:55 PM

Quote:

Originally Posted by jenchris

I point my scope by shining the laser down my ep hole the beam is amazing and I dont need a sighting scope.
I expect doing two at once may combine them.

Are you sending messages into space?

When I get my two, I'll experiment with Blutack and see how it might be useful for aiming a telescope.
Cheers,
Renato

sharpiel · #9 12-09-2014, 10:19 PM

Remember Ghostbusters... Care when crossing the beams

LewisM · #10 12-09-2014, 10:28 PM

Bunching 10000000000000000000000000000000000 000 laser pointers individually is not going to intensify the beam - you have to COMBINE them into one coherant beam.

The best way is simply to get a higher wattage laser.

jenchris (Jennifer) · #11 12-09-2014, 10:44 PM

Out of phase light from two sources will interact and diverge is what you're saying?

big_dav_2001 (Davin) · #12 12-09-2014, 10:58 PM

All you will get is a bunch of parallel beams, each only as bright as the individual wattage... If you can't see one beam from 2m away, you won't be able to see 5 parallel beams (or however many you use) from 2m away because they will not be any brighter than the individual because they are parallel...

If you focus all the beams into one, only then will you see any increase in overall brightness...

Davin

RB (Andrew) · #13 12-09-2014, 11:02 PM

... and there's no practicle way to focus/combine the beams unless you use a beam combiner.

Renato1 (Renato) · #14 13-09-2014, 12:36 AM

Quote:

Originally Posted by sharpiel

Remember Ghostbusters... Care when crossing the beams

I always enjoy that film - but darned if I can remember that reference at the moment.
Cheers,
Renato

Renato1 (Renato) · #15 13-09-2014, 12:37 AM

Quote:

Originally Posted by LewisM

Bunching 10000000000000000000000000000000000 000 laser pointers individually is not going to intensify the beam - you have to COMBINE them into one coherant beam.

The best way is simply to get a higher wattage laser.

But that requires a $60 a year licence!
Cheers,
Renato

Renato1 (Renato) · #16 13-09-2014, 12:41 AM

Quote:

Originally Posted by big_dav_2001

All you will get is a bunch of parallel beams, each only as bright as the individual wattage... If you can't see one beam from 2m away, you won't be able to see 5 parallel beams (or however many you use) from 2m away because they will not be any brighter than the individual because they are parallel...

If you focus all the beams into one, only then will you see any increase in overall brightness...

Davin

Hi Davin,
If one beam sends X amount of photons to my eyes, or to the eyes of people tracing the beam with binoculars, wouldn't 5 beams send 5xX amount of photons towards our eyes?

If X=0, then I agree, it would be pointless, but I'd hope the value was higher than that.
Cheers,
Renato

Renato1 (Renato) · #17 13-09-2014, 12:49 AM

Quote:

Originally Posted by jenchris

Out of phase light from two sources will interact and diverge is what you're saying?

No, I was just wondering if five parallel beams from five 1mW lasers (where each beam can be seen as a ray going into the sky) would nearly as good as a 5mW laser, or not much good.

So that if the combined lasers were nearly as good at pointing out celestial objects as with a 5mW laser, when the Police come knocking I could show full compliance with the law.

Cheers,
Renato

Renato1 (Renato) · #18 13-09-2014, 01:01 AM

Anyhow - curiosity has gotten the best of me. I just ordered another three lasers.

I'll have a definitive answer next week as to whether it's a good idea or whether my niece and nephews get a laser pointer in their Christmas stockings.
Cheers,
Renato

sharpiel · #19 13-09-2014, 07:44 AM

Quote:

Originally Posted by Renato1

I always enjoy that film - but darned if I can remember that reference at the moment.
Cheers,
Renato

http://m.youtube.com/watch?v=jyaLZHiJJnE

Beams...streams...same, same. Don't destroy the universe!

ericwbenson (Eric) · #20 13-09-2014, 10:16 AM

Five lasers can make five parallel beams, getting them parallel and keeping them there you will find to be <extremely> difficult. But if you could do it to within an angle less then the beam divergence (about 1 mrad or so, which is ~3 arc minutes !!!) then at a distance the five beams will overlap and it will appear brighter. That distance depends on how close you can get the barrels and the beam divergence. Unfortunately that distance might be so far away that the five times intensity gain is swamped by the 1/r^2 intensity drop due to distance, so it may gain nothing.

The beams are not coherent (aka in phase) with each other but for the purposes of scattering off dust particles that doesn't matter.

BTW you can't use a beam combiner for lasers of the same wavelength, you can combine two linearly polarized lasers, but that's it.

Best,
EB