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Measuring wattage of laser?

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Hello,

I am new here and recently purchased a 405nm 5mW laster pointer from ebay. It is a pretty unknown source from china and i know that sometimes these lasers are much higher than 5mW.

I want to know what equipment i would need to measure the wattage of my laser when it arrives. I have some electronics equipment am not new to soldering circuits.

Thanks for the advice!
 

Lotus_Darkrose

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The most basic power meter I've seen is this one for $69.99:

Products

It does require that you have a DMM for the reading and the meter is limited to 200mW maximum.


The other approach is found here:

http://laserpointerforums.com/f70/what-if-i-don-t-have-lpm-82018.html#post1178471



Bob Diaz
There is no point in spending $69.99 + $18.99 shipping on that whatsoever. You can buy a Radiant X4 and a plastic enclosure for $109.45 shipped. Only $20.47 more to not get ripped off.

Radiant Electronics : Illumination Supply, Quality Flashlights and More!
 

ScottW

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Welcome to LPF, sudosilman!

There are a lot of options for Laser Power Meters. Member ARG put together a list containing many of them, with prices and specs. Here's a link:
https://sites.google.com/site/argslasers/guides/buyersguide

I just went through the selection/buy process myself. Some key things to consider are:

  • What is the maximum power you want to measure?

  • What response time do you need? The less expensive sensors are slow to respond, needing 30-60 seconds to get a final measurement. This impacts getting a proper "peak" reading for lasers that peak early and fall off in power or have a short duty cycle. It also means they cannot capture "instability", the power fluctuations common in DPSS lasers. If either of these are important to you, you may want something with an Ophir sensor -- they are FAST but are also expensive and in short supply.

  • Do you need a standalone display? Some meters have a display, some only record via computer, some have both. Still others use a connected DMM to take the reading.

  • Do you want to log/graph results by computer? If so, you'll want one that supports data logging.
I eventually decided on the Radiant X4, which is a great deal at $99. It handles up to 3.7W, and has both standalone display and computer logging. But it is fairly slow response, so can't capture DPSS fluctuations or early peaks. Still, for the price it is an excellent way to get a basic power reading.

Good luck. There is an entire sub-forum devoted to Laser Measurements so browse around there and post some questions if needed.

Also -- please take a moment to place an "introduction" thread in the "Welcome" section, and update your profile to show your geographic location. Knowing where you are in the world can often affect what products/help members suggest. Have fun & be safe!

---Addendum---
There is no point in spending $69.99 + $18.99 shipping on that whatsoever. You can buy a Radiant X4 and a plastic enclosure for $109.45 shipped. Only $20.47 more to not get ripped off.

Radiant Electronics : Illumination Supply, Quality Flashlights and More!
^^ 100% agree with this.

That JBauer HLPM-II has no display (requires using your DMM), no data logging, requires that you use correction charts and calculations for anything other than 650nm, and is limited to 200mW.

For just ~$20 more, the X4 has 3.7W (3700mW) max, standalone display and USB data logging, AND doesn't require the use of correction charts/calculations.
 
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Thanks for all the replies!

I am really not looking to spend much money (more than 30 dollars) for purposes of measuring the beam since it doesn't truly affect how i use it (i simply wanted to know out of curiosity). Is there any way i can build a shotty Laser Power Meter myself? I feel like it shouldnt be more complicated than a solar cell hooked up to multi-meter.

What cheaper options do you guys know for measuring beam power?
 

ARG

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$100 is already considered to be really cheap for an LPM. Budget LPM's from other sellers are typically over $200.
 

ScottW

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Thanks for all the replies!

I am really not looking to spend much money (more than 30 dollars) for purposes of measuring the beam... I feel like it shouldnt be more complicated than a solar cell hooked up to multi-meter.
Well, it is more complicated... There are good reasons why thermopiles or TECs are used rather than photovoltaic devices for LPM sensors. There are some threads here on LPF discussing the issues/challenges. You can search the forum for more, but here are a couple examples to start you off:
>>http://laserpointerforums.com/f42/incredible-semi-accurate-results-free-lpm-63503.html
>>http://laserpointerforums.com/f44/solar-panel-driven-lpm-63478.html

Given your price limit, your best bet may be finding a LPF member near you who has a calibrated LPM -- or even mailing your laser(s) to a TRUSTED member to measure and return them.
 
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ultimatekaiser

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Given your price limit, your best bet may be finding a LPF member near you who has a calibrated LPM -- or even mailing your laser(s) to a TRUSTED member to measure and return them.
This was going to be my suggestion. Most members including myself will meter it for free, just pay shipping to and from. if you live in the US I can do it for you on a very accurate lab LPM
 
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Wow thats amazing! You guys are so generous!

I live in Davis, CA so if anyone wants to measure it for me and is nearby i would gladly mail it to you (and pay for return shipping as well).
 

ScottW

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KapHn8d

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ScottW beat me to linking the member thread of LPM owners willing to help with measurement. Go there and check it out.

Cheers!
 




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