- Mar 25, 2016
Anyone have a laser power meter that can measure up to 10 Watts and want to sell me it? I looked all over the internet and the cheapest one was like $900. Does anyone know of one for around $200?
Can't you get the Ophir for $300.00? You'll need to set it up with two power supplies and a voltmeter readout. I think if you supply the sensor with a +12 and a -12 volts it will read over ten watts. Otherwise, one will eventually pop up on eBay if you look long enough.
As far as i know from dissassembling the ophir head (which used internal amplifier), they're using 78L08 for the positive rail and 79L05 for the negative rail. Meaning the supply for the opamp inside is +8 and -5.Can't you get the Ophir for $300.00? You'll need to set it up with two power supplies and a voltmeter readout. I think if you supply the sensor with a +12 and a -12 volts it will read over ten watts. Otherwise, one will eventually pop up on eBay if you look long enough.
Unless you're talking about this
Ophir 150W A 0 04 Y Thermopile Laser Power Meter w Built in Amplifier | eBay
What do you all think about using a non-polarized beam splitter cube for measuring a 10W laser with a 5 watt LPM? I'm thinking that would work if you knew the loss across the wavelengths the cube is used at.
I'd just go for a 50/50 beam splitting cube/mirror for whatever wavelength you want to test. Actually, you could go 90/10 if you wanted - as long as you know how much is being split off. That way it won't care how the diode is orientated - with a PBS it will.
oh hey that's a great idea! So just split it 50/50 and double the reading then? that might work, however with the NUBM44 the beam divergence is kind of hard to split right down the middle...
A 50/50 beam splitter is a mirror that passes 50% of the entire beams power and reflects the other 50% - it doesn't just slice the beam down the middle. :beer: It's essentially a fancy partial mirror - same goes for the non-polarizing beam splitting cubes - they are just a cube instead of a "plate"... Which offers some different benefits over plates, see Edmunds page below for more on that.
Thorlabs has them: https://www.thorlabs.com/navigation.cfm?guide_id=18 - any type of beam splitter/sampler you could ever want.
Usual detailed explanation from Edmunds: What are Beamsplitters?
If you get a NON-polarized beam splitter cube try to find one with AR coating for the wavelength you are measuring to reduce the loss. If you buy a mirror from this guy on ebay, he really knows his stuff and can measure the loss for you so you can have an accurate reading:
bjomejag | eBay
Edit: I did some searching on his ebay store and found this 90/10% mirror which is good across the entire visible band plus some; from 350 to 850nm: Optical Filter Neutral Dichroic 90 Reflect 350 to 850nm ND 1 0 Sputtered 50mm | eBay
Just measure the 10% beam, that way you could measure the output of a 10 watt laser with a 1 watt laser power meter. I'd also buy a holder for the mirror on a small stand of some kind, otherwise you will have a floppy mirror which could cause the beam to go where you don't want it to go.