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11-02-2013, 07:15 PM #1
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lasermanXYZ
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calculating laser power output

...when i use the formula P=I*V considering V the voltage of the batterie and measuring I when I connect my multimeter in series when my laser is on.

is that the same power reading which is given approx. on the laser label or when we talk about mW of lasers in general?

11-02-2013, 07:22 PM #2
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shokkunlasers
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Re: calculating laser power output

No that's only the input Power Pin without efficiency of driver diode and lens

The power we are talking about is optical output power.

((Pin*efficiency_driver)*efficiency_diode)*efficie ncy_lens = optical output power

11-02-2013, 07:30 PM #3
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lasermanXYZ
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Re: calculating laser power output

...yeah, would have been to easy that way. but i read it somewhere and wasnt sure about it...

11-02-2013, 07:35 PM #4
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Tmack
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Re: calculating laser power output

The efficiency of each diode varies so much . That's why one cannot calculate without an lpm. A 9mm run at 2.25a can put out 2.3w. Up to 3.5w. Over 1000mw difference.
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11-02-2013, 08:16 PM #5
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ARG
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Re: calculating laser power output

Yeah, only way to know is with an LPM.

Check out DIY Ophir LPM's if you're interested.

11-04-2013, 09:47 PM #6
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lasermanXYZ
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Re: calculating laser power output

Quote:
 Originally Posted by ARG Yeah, only way to know is with an LPM. Check out DIY Ophir LPM's if you're interested.
no skills, no money, no time... but tomorrow i can test the LPM of my university

11-04-2013, 10:20 PM #7
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BShanahan14rulz
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Re: calculating laser power output

Make sure you tell them what the max power that your laser could be capable of. You don't want to test it on a sensor whose max power handling is 5mW, when your laser is spitting out a watt of optical power.

11-06-2013, 12:52 PM #8
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lasermanXYZ
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Re: calculating laser power output

soo, there i was and it was humiliating. it turned out that my 75mw pheonix was only worth 30mw. i literally was crying. how could this happen? its 6y old but was used only about 1-2h in sum. we also measured one of those cheap <200mw pens which actually was about 100mw.

btw the sensor used was a "thermo-sensor"
here some pics
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11-06-2013, 01:18 PM #9
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pschlosser
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Re: calculating laser power output

Welcome to the world of truth. Don't feel bad, we've all been there.

But first chance you get, seek a second opinion from a different LPM. And make sure the batteries are fully charged.

edit: I thought thermo-calorie-counting sensors had to be powered. If that one is simply photonic, adjustments must be made for differing wavelengths.

Last edited by pschlosser; 11-06-2013 at 01:23 PM.

12-10-2013, 10:22 PM #10
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lasermanXYZ
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Re: calculating laser power output

Quote:
 Originally Posted by pschlosser Welcome to the world of truth. Don't feel bad, we've all been there. But first chance you get, seek a second opinion from a different LPM. And make sure the batteries are fully charged. edit: I thought thermo-calorie-counting sensors had to be powered. If that one is simply photonic, adjustments must be made for differing wavelengths.
on the second run it gave a better 60mW. adjustments, hmm like what?
u center the beam in it and then it produces 0,16v for each mw. using ur calc. u got ur power output.

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