How much power for a green laser (pointer) to be visible in bright sunshine?

wus

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When I was in Papua I took a jungle tour with a local birding guide. He used a small green laser pointer (pen style, I guess powered by 2 AAAs) when I didn't see the animal that he was trying to show me. It was strong enough that the green point could be seen even somewhere between 50 and 100 meters (estimated) away, in full bright tropical sunlight.

I asked him what power the pointer has, but he didn't know, and there was no brand or model number whatsoever on it.

Can anyone here give me an idea how much power is needed for this scenario?
 

KITROBASKIN

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Definitely not informed about lasers, but purchasing a green laser with an 18650 sized compartment from that manufacturing behemoth country, might very well get you the power you want. The one I got from a friend had a type of novelty light splitter that can revolve and completely unscrew. This may be how they sell such strong lasers beyond what our country officially allows. Also, the 18650 battery that came with it was very light in weight; not a full size 18650 internally but it worked. Also good to know is that the positive end of the battery faces the tailcap in my unit.
 

markr6

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Definitely not informed about lasers, but purchasing a green laser with an 18650 sized compartment from that manufacturing behemoth country, might very well get you the power you want. The one I got from a friend had a type of novelty light splitter that can revolve and completely unscrew. This may be how they sell such strong lasers beyond what our country officially allows. Also, the 18650 battery that came with it was very light in weight; not a full size 18650 internally but it worked. Also good to know is that the positive end of the battery faces the tailcap in my unit.

Sounds like mine as well. I purchased two from ebay. Searching "301 green laser" on ebay will show those from various sellers. Mine vary a bit but they're both "5 mW", which is likely at least twice that in reality. They're visible in sunlight, depending on what you're pointing at. Even a bright white house could probably be painted with that thing. Not bad for $10!
 

PhotonWrangler

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I've seen those "303" lasers. Their output can be anywhere from a few milliwatts to upwards of 50mw. They're not well calibrated and they often don't include an IR blocking filter, so some of the output power can be in the invisible 808nm and 1064nm wavelengths. That's enough to cause eye damage if you accidentally aim it at something reflective. Be careful.
 

wus

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Thanks for your thoughts.

@KITROBASKIN, what type or model do you have, with that novelty light splitter?

Instead of 18650 I'd prefer something very slim and compact (pen style, but rather shorter than the apparently common type designed for 2 AAAs), running, e.g., off a single 10440 sized LiIon.

@ PhotonWrangler (and all :) ) - is there an easy way to find out if a green laser pointer has an IR blocking filter? Something like a sensor that I could use if I'm in a shop trying out laser pointers that they sell?

The question remains, how much power do I need?
 
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KITROBASKIN

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Both my tail switch (not as bright but still powerful) and simple side button unit are not labeled as to manufacturer or vendor.

I was also given a red laser that uses 2 AAA (I believe) that is not powerful like the green lasers powered with nominal 4 volts. If you can go into a shop to try it out, that would be good.

I would not trust power claims made by sellers or makers of these cheap models. So asking for how much power needed to see in daytime is not something I would seek.
 

PhotonWrangler

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@ PhotonWrangler (and all :) ) - is there an easy way to find out if a green laser pointer has an IR blocking filter? Something like a sensor that I could use if I'm in a shop trying out laser pointers that they sell?

If you're able to unscrew the optical head to reveal the laser diode, the IR filter is a little square of greenish colored glass glued to the output of the laser diode. That's the most direct way to tell.

If you had an optical power meter (or even an old camera light meter), aim the laser at the meter and note the optical power. Then place a red filter (preferably glass) in the path to knock out the visible green light. If the power meter still shows a reading from the laser, there's probably no IR filter in place because you're reading the presence of IR on the meter.
 
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