silver laser putting out ir as well as 532??

Hello

I am importing lasers, I have found a manufacture (that I am not going to mention) I have a couple of samples from them a 20mW and a 50mW the lasers are the same as the ones from this post http://candlepowerforums.com/vb/showthread.php?t=118864

When I tested the 20mW lasers with my energy concepts laser power meter it tested to be about 15mW normal.

When I tested the 50mW laser it came out as -8mW (that's right negative)

If I shine ir in to the meter it comes out as negative, So I am assuming that this laser is putting out more ir than 532nm light.
I had the optics from another laser and I took the ir filter out of it and put it in front of the 50mW laser and tested it again. I read 23mW.

The <50mW beam looks brighter than the <20mW and the <50mW will burn through a black rubbish bag in less than one second.

Has anyone got a laser meter and tried shining some ir in it from the laser before it shines through the kpt?

Any comments or help would be good as I don't want to sell lasers that are putting out dangerous amounts of ir

2x lasers with ir filter

The IR filter and ktp are not the same thing, or did I mistaken what you were trying to say?

Anyway IR will give you false readings if your meter is calibrated to 532nm. On a Lasercheck meter it will show it as a higher output then normal, but it is likely having an effect on your readings there. If one is brighter it is not outputting less.

Because the ND crystal is usually a hybrid ND/KTP once you remove it you will have 808nm IR not 1064nm. The output would be 300-500mW depending on what power of pump diode was used(probably 350mW).

Hello. What I was trying to say has any one tried shining the ir from a green laser pointer in to a laser power meter. (the ir light before it gets converted to 532nm)

Or the light from a laser with out a ir filter in it to see if you get a higher or lower reading.

Oh, yeah you will get a fasle reading, usually higher then it is supposed to be...well with a Coherent Lasercheck meter anyway, I'm not ure about the brand you have. However because the meter is supposed to be calibrated for 532nm the added IR will make the result completely off. If you want to measure the IR you will need to block the 532nm and calibrate your meter to 808 or 1064nm to get an accurate reading.

I think athoul is right on. And you knew what was happening, it's exactly what we guessed what was happening in the link you posted - the manu has left the IR filter out of the 50mW to boost its power. If your test filter is flat (not a lens) then the meter reading with it in front of the laser is it actual green output power, or 23 mW.

To clarify, there are two IR wavelengths - the 808nm diode, and the ND created 1064. Without the crystal, the IR output will be 808, with the crystal and no filter, the output lines will be 532 and 1064nm.

If you are to be importing these, you need to instruct the manu. to include a IR filter. But, then, I'm guessing, they won't be able to offer a '50 mW' model anymore!

Selling any pointer classed as 3a/b and a greenie without an IR filter should be banned outright - and customs blocking all shipments from that seller. IR is very dangerous and v.high power IR coming out of it is a very stupid situation to place people in.

If the manufacturer is letting high levels of IR out on purpose just to sell high power greenies they need locking up - not that that will happen seeing they all seem to be based in china.

Thanks for clearing that up. I am going to contact them about it and see what they say. I have no way of proving that there is no ir filter inside the laser with out destroying it because I cant tune my meter to a different wavelength.

The test filter is flat so I assume that atcual power is around 23mW.

Another company that I was dealing with were selling <50mW lasers that were actually about 10-18mW and this was a well known company. I sent them all back to them and they are going to sort the problem out (I hope they dont just remove the ir filters)

I will post the reply after I have contacted them.

Yes, I'd like to know this info right away as I just bought that 50mw pointer from thegreenbeam.com two weeks ago and have been playing with it a LOT.

Three pics and a vid of my pointer popping a balloon can be found in this thread: http://candlepowerforums.com/vb/showthread.php?t=120088

I'm very concerned about my eyeballs at the moment and I don't have any way to check this for i.r. output.

The IR filter is usually a blue or green coloured glass piece right behind the collimating lens. In some cases it's not right there though, so because you don't see it, it may not mean it's not there but perhaps further back. With such readings though, I also agree that the IR filter is probably not there.

Apex007 said:

Yes, I'd like to know this info right away as I just bought that 50mw pointer from thegreenbeam.com two weeks ago and have been playing with it a LOT.

Three pics and a vid of my pointer popping a balloon can be found in this thread: http://candlepowerforums.com/vb/showthread.php?t=120088

I'm very concerned about my eyeballs at the moment and I don't have any way to check this for i.r. output.

Click to expand...

I will keep you posted. For now just close one eye when you are using the pointer so if you do go blind at least you will have one good eye. (just kidding)

I just got a reply .

____________
They wanted to know the range of my laser meter. They also said they tested it to be over 50mW before they sent it out and infomred me that they are using a seperate ir filter.
________

I have not measured anything over 20mW with my laser power meter before. So either they not telling the truth or my meter is stuffed.

I just had an idea when I was writing this. I will put the laser meter up to the light bulb and see what happens.

Results: As I get closer the power reading climbs up to about 20mW (I know this is a different wavelength) then drops down to -2mW and keeps falling. This would explain the negative reading I got when I pointed a ir diode in to the meter from a green laser.

So. It looks like I need a new power meter, any suggestions?

Cheers for you help

Athoul said:

The IR filter is usually a blue or green coloured glass piece right behind the collimating lens. In some cases it's not right there though, so because you don't see it, it may not mean it's not there but perhaps further back. With such readings though, I also agree that the IR filter is probably not there.

Click to expand...

When I look down into the lense (with the batteries out!) I can clearly see a green/blue tinted color down in the assembly. IIRC the MCA does is colorless so that may be evidence of an IR filter.

Also, I want to mention that I have a tweaked Leadlight putting about 15mw. This <50mw is waaaaaaay brighter, so much so that I can't look at the spot. I still have confidence that it's not an IR issue. I think it's just putting out well over 50mw of green.

Two nights ago I hung a roll of heavy-duty 1.5" black electrical tape from my kitchen table. I put a light amount of tension on the tape and panned the laser right to left from about 5" away. Within 15 seconds it sliced through the entire 1.5" with ease.

rapt said:

I just got a reply .

____________
Thanks for your email.
May i know the range of your laser power meter?
As for 50mW laser we submited you, the testing result about it here
actually was more than 50mW.
We use a seperate infared filter for the laser pointer and make sure
all the infared light being filtered out.
Regards,
__________

Click to expand...

Hopefully that is the case, and it does seem to make sense. If my pointer was only around 20mw putting out the rest of the energy in IR, it would't be as bright as it is. Like I mentioned above, it blows away my ~15mw potted Leadlight.

Thanks for getting back so quickly with the response!

Interesting, and somewhat relieving if this is the case. You can try to do a green LED test: take a baseline uA reading of the green led (using a multimeter in uA mode) with 5mW and 15mW pointers, then extrapolate that line to get the mW result from the 50mW laser. This should give you a decent approximation. Don't forget to use the peak reading after the laser has been on for 5 seconds. Move the diode around in the beam a little to get the peak reading.

rapt ... posting private communiaction content without the explicit permission of the other party isn't permitted on CPF. You can describe and re-word the content, but not quote it, sorry.
I edited your post accordingly.
Thank you.
bernhard

Hello. I did not know that you could not post e-mails. I did edit out the names as I thought that would be enough.

I will buy a green led today and do a uA test and calabrate it with my laser power meter and a lower power laser. I will post the results. I am told by the manufacture that they did measure it at over 50mW.

If you're really curious, you can shine the beam through a prism, and view with a webcam modified to pick up IR. That way, you can see where the where the IR beam is hitting with the webcam and measure its intensity with a power meter. I've tested various green lasers (leadlight, some ebay ones) and they've been pretty good in not leaking 808 or 1064 IR energy.

Many meters are calibrated for a particular frequency, so you may have to use some correction factor to get the actual measured power.