Results 1 to 6 of 6

Thread: extending the range of my laser power meter

  1. #1
    Join Date
    Nov 2014
    Location
    mid michigan
    Posts
    742

    Default extending the range of my laser power meter

    a while back I wanted to up the power my meter can read it tops at 40mw and some people had mention wedge type prisms to act like a beam spittle
    but I can fond the original threat, my question to that is what angle should the wedge side have?
    I was also thinking of adding resistors to the sensor to lessen it's output, I guess for quick measurements that would work but still not exactly sure.
    thanks for any info you guys may have
    I now have a class for green as well so a filter for the sensor or a wedge may be the way to go? or adding like a divide by 2-10 times would may work as well, I have a higher power meter on loan so I have a reference to use, the beam splitters I have tried sis not have a repeatable or predictable result for some reason
    Polk SDA SRS, Luxman M117, Onkyo 504, 7.62X39, sometimes a ball on a string is the greatest of toys for us nonhuman types. oh and some lasers, lots of lasers

  2. #2

    Default

    What type of LPM are you referring to ?? Optical or Thermal ??
    A resistor in series with any sensor would definitely un-calibrate
    a calibrated sensor
    You could use a Neutral Density (ND) Filter buy you would need
    test the Power Reduction ratio at the specific wavelength of your
    Laser under test. The same ND filter does not necessarily have
    the same Power Reduction ratio at different wavelengths..

    At.. for example a 10 x reduction your reading resolution will
    drop 10 fold.


    Jerry
    See the LaserBee II and all other LaserBee LPM products here....
    All LaserBee Laser Power Meter Products

    New 3.2Watt RS232/USB LaserBee II LPM REVIEW


    Always in stock and ready to ship....
    Subsidary:-Pharma Electronic Solutions

  3. #3
    Join Date
    Oct 2012
    Location
    Germany
    Posts
    705

    Default

    ... you can stack several filters to add the reduction (virtually limitless) - but, as Jerry says, you have to measure the "reduction" of one (or a fixed number of) filter(s) for every wavelength to get correct numbers ...

    Viktor

  4. #4
    Join Date
    Jun 2009
    Location
    St. Louis, MO
    Posts
    534

    Default

    Google Hershel wedge
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  5. #5
    Join Date
    Nov 2014
    Location
    mid michigan
    Posts
    742

    Default

    sorry for the late reply but the meter I have is an optical type
    http://www.ebay.com/itm/Sper-Scienti...0AAOSwaApZkH-g

    it's mot linier but comes with a correction table,

    Now for a wedge prism what should the angle of incidence be? I have seen a few that have different slopes if you will
    Polk SDA SRS, Luxman M117, Onkyo 504, 7.62X39, sometimes a ball on a string is the greatest of toys for us nonhuman types. oh and some lasers, lots of lasers

  6. #6
    mixedgas's Avatar
    mixedgas is online now 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
    8,807

    Default

    Companies that sell good wedges know what the index of refraction is for the glass they use. With that and the wedge angle, you can calculate the Fresnel reflectance for the wedge. I would imagine something 20 degrees or less is a good start.

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

Posting Permissions

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