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Community calibration

Tmack

Tmack

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Was thinking about starting a small fund for a 500mw red lab laser (recommend by our resident LPM ologist) that's exceptionally stable, that we could first send to a known calibrated LPM, then send to members on a list. That way, the members involved could calibrate their lpms to one central meter. What do you guys think? Since we all pass lasers back and forth like S. T.... Err.... A cold..... We could all benefit from having centrally calibrated lpms.
 





Sounds like a great idea- as long as someone doesn't run off with the unit!

then again I don't have an lpm, soooooo.....yeawhatever.
but certainly, if its stable at constant power, that would be a great calibration tool for sure.
 
Problem is, someone could change their mind and keep the laser to himself.
 
Tmack said:
to a known calibrated LPM
Click to expand...

Should be someone with a Coherent fieldmax. A few members have them. Wouldn't be right to do it on a meter that's calibrated, but still 1% out :p
 
Well do you guys think we should have some kind of rep/post requirements? I personally wouldn't trash my name here for a couple hundred dollar laser.
 
I'm all the way in! :beer:
And in order to elliminate the loss of the laser we can also charge the member who has it the price of it and refund him when it reaches another member...it is kinda complicated though...

Jim
 
I'd prefer to just have it kept with a single reputable and knowledgeable member who doesn't mind the responsibility of operating and managing the hardware for others, while having guaranteed access to it all the time. Then we just send our meters, lasers, etc. to him/her and get the data back with our hardware.

The benefit is that we don't have to deal with vetting out certain people, insurance, shipping times, wait times, etc. I'd also be wary of having the laser damaged or lost in transit, or mishandled by someone who doesn't really know how to use it (e.g. burning the sensor). Plus, there will be other people who will want to use this service that we don't want to ship the hardware to. Another good thing is that the conditions of measurement would remain the same so that we don't have to question the methodology of measurement, not just whether we have a reference source.

The service wouldn't have to be free, or maybe it could be free for those who chipped in for the meter/laser. Otherwise, people could just pay something like $5/laser or $10/meter + shipping to have them metered/calibrated. It would pay for the time of the operator and the cost of the hardware.

Another advantage is that we could buy other hardware to centralize as well. Spectrometers, beam profilers, etc. could all be purchased and also upgraded over the years. We could have a big database of all different parts such as lenses, diodes, lasers, etc. which would be a great benefit to everyone.
 
Generally that's a nice idea if no idiot keeps it for himself :undecided:
Of course it has to be a module with photodiode and maybe also TEC controlled,
because we won't test our meters at the same Temp.
So maybe a plus 200$ one.

But there's a snag to it we can only calibrate our meters at one single wavelength if we want to be precise, because the coating on the sensor doesn't absorb every wavelength equal.

Nearly every Ophir head owned by forum members is calibrated to 1064nm light

For high quality coating like those on the ophir heads that's no big deal, but I don't know how that would apply for TEC units.

Therefore I think that the precision for all wavelengths is maybe 2-5% and we can't really measure to a point of single milliwatt.
 
First of all, this is a hobby. I've said this before and I don't care if mine reads 500 mW and yours reads 531.785 mW.
Also, most of us with LPM's don't need another laser!!!! I have my share.
HMike
 
Temp will play a factor so even of its stable there will be diferences between everyone's readings
 
I like the idea of someone willing to test our lpms and receive a tip for their time and effort
 
It could be done where the owner of the laser collects say 150% of the cost of the laser from whoever wants to borrow it. Upon return of the laser the owner then refunds the borrower. This creates a disincentive (I'm not sure if that's even a word) to keep the laser.

I don't care if my LPM reads 500 and yours reads 531.43, however I have an old used LPM that I got for a VERY good price, but truth is, mine might read 250 and yours may read 531.43 and I'd really have no idea.

Do LPM's meter different WL's differently? I thought I remembered reading that coherent models (one just one in particular) didn't meter 405 accurately. I could also be horribly mistaken on that though.
 
Last edited:
Javalin said:
Do LPM's meter different WL's differently? I thought I remembered reading that coherent models (one just one in particular) didn't meter 405 accurately. I could also be horribly mistaken on that though.
Click to expand...

Yeah, some thermal meters will not readily absorb lower wavelengths. Most of the new ones are fine now.
 
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