Results 1 to 10 of 10

Thread: Power Meter Suggestion?

  1. #1
    Join Date
    Oct 2006
    Location
    California, USA
    Posts
    38

    Default Power Meter Suggestion?

    Looking for a new power meter. Something a bit robust that I can use in the field.

    I'm drawn to the Thorlabs PM310D.

    http://www.thorlabs.com/newgrouppage...4216&pn=PM310D

    What is everyone else using?

    Best,

    Greg

  2. #2
    mixedgas's Avatar
    mixedgas is offline Creaky Old Award Winning Bastard Technologist
    Infinitus Excellentia Ion Laser Dominatus
    Join Date
    May 2007
    Location
    A lab with some dripping water on the floor.
    Posts
    8,925

    Default

    Look, I love Tlabs, but under no circumstances buy that product. When I was a FSE we often were at issue with customers who used those, vs our NIST traceable power meters. We would see errors of 20-30% on the Tlabs product. We urged several customers to return those, and they did. The repeatability was good, but the absolute calibration was way off.

    Of a 4 unit sample, from multiple batches, 3 had serious discrepancies.

    Steve
    Last edited by mixedgas; 07-15-2014 at 12:05.
    Qui habet Christos, habet Vitam!
    I should have rented the space under my name for advertising.
    When I still could have...

  3. #3
    Join Date
    Dec 2009
    Location
    Laurel, MD
    Posts
    289

    Default

    I have no experience with the Thorlabs unit, but for less than that price you can get the Coherent Powermax LM-10, which is great for using on site. USB only, so it packs very compact, nice and rugged, annual recalibration from Coherent is priced very reasonably. The big disadvantage is that you have to have a laptop or windows based tablet to use it, but I really can't think of any time I've gone out to a customer site and haven't brought a computer with me anyway. You can buy a lot of lab snacks with the hundred bucks you save.

  4. #4
    Join Date
    Dec 2007
    Location
    Nottingham, UK
    Posts
    2,744

    Default

    Steve...
    I thought the calibration data was stored in each sensor, not the PM100D, and the sensors are NIST traceable.
    So it shouldn't have been a problem; can you elaborate a little?
    What exact head was used?

    Regards,
    Dan
    - There is no such word as "can't" -
    - 60% of the time it works every time -

  5. #5
    Join Date
    Nov 2008
    Location
    Cleveland Ohio
    Posts
    1,756

  6. #6
    mixedgas's Avatar
    mixedgas is offline Creaky Old Award Winning Bastard Technologist
    Infinitus Excellentia Ion Laser Dominatus
    Join Date
    May 2007
    Location
    A lab with some dripping water on the floor.
    Posts
    8,925

    Default

    Quote Originally Posted by danielbriggs View Post
    Steve...
    I thought the calibration data was stored in each sensor, not the PM100D, and the sensors are NIST traceable.
    So it shouldn't have been a problem; can you elaborate a little?
    What exact head was used?

    Regards,
    Dan
    Dan, PM sent.

    Steve
    Qui habet Christos, habet Vitam!
    I should have rented the space under my name for advertising.
    When I still could have...

  7. #7
    Join Date
    Dec 2007
    Location
    Nottingham, UK
    Posts
    2,744

    Default

    Steve,
    PM not received. Can you check/resend?
    Cheers,
    Dan
    - There is no such word as "can't" -
    - 60% of the time it works every time -

  8. #8
    Join Date
    Oct 2006
    Location
    California, USA
    Posts
    38

    Default

    Thanks all for the comments.

    I like the LM-10 but I am on a Macbook using Parallels and Windows. Hopefully it would still work.

    Quote Originally Posted by araugh View Post
    I have no experience with the Thorlabs unit, but for less than that price you can get the Coherent Powermax LM-10, which is great for using on site. USB only, so it packs very compact, nice and rugged, annual recalibration from Coherent is priced very reasonably. The big disadvantage is that you have to have a laptop or windows based tablet to use it, but I really can't think of any time I've gone out to a customer site and haven't brought a computer with me anyway. You can buy a lot of lab snacks with the hundred bucks you save.

  9. #9
    Join Date
    Aug 2012
    Location
    Reading, UK
    Posts
    180

    Default

    Quote Originally Posted by kecked View Post
    That looks to be great for the mw range only though
    In science one tries to tell people, in such a way as to be understood by everyone, something that no one ever knew before. But in poetry, it's the exact opposite - Paul Dirac

  10. #10

    Default

    It depends what you want to use the power meter for.

    For checking the performance of a laser projector’s output, use a meter with a thermal detector head. These have a fairly broadband response, meaning they can be used to be measure the total power output of several beams of differing wavelengths simultaneously, and are available to measure high power outputs of several watts or more.

    If you want to check a laser beam to determine safe exposure for an audience scanning application, standard thermal detectors are generally not suitable; they are too slow to react, and don’t have the resolution (unless you use one of the high sensitivity devices, but the maximum power they can measure will be limited to typically less than a watt, and they still have a (relatively) slow response time).

    For measuring exposure levels, the better option to get an instantaneous reading is to use a photodiode based detector. These provide the sensitivity and resolution to measure what will be in the mW region. The downside is that they will only give an accurate reading for one wavelength at a time, so it makes measuring a multicolour beam more difficult.

    The simple thing to remember is :

    Measure Power = Thermal Detector
    Measure Exposure = PD Detector

    Given that some people will want to measure both these things, then buying meter that can accept multiple detectors is something to consider.

    As far as the Thorlabs kit you mentioned is concerned. I have no experience with that specific detector, but do have some good recent experiences with the same meter and some other detectors of theirs. Maybe the problems with the calibration have been resolved.

    I had a similar problem with another major manufacturer’s meter/detector combination. One detector type was fine, but the other caused me lots of problems giving a consistent >15% error, even after being recalibrated by the manufacturer twice. I know this sort of experience does knock your confidence in the manufacturer.

    I have a selection of meters from Coherent, Ophir, ILT and others, and each has its own benefits / nuances.

    James
    Laser Safety
    http://www.lvroptical.com
    http://www.facebook.com/LaserSafety

    - Laser Show Safety Training, Assessment, and Realtime MPE Measurement
    - Pangolin PASS System Integrator

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •