Page 1 of 3 123 LastLast
Results 1 to 10 of 26

Thread: Can you use a beam splitter to combine beams?

  1. #1
    Join Date
    Nov 2013
    Location
    State of Shock USA
    Posts
    608

    Default Can you use a beam splitter to combine beams?

    Picked up one of these for 55% off. http://www.surplusshed.com/pages/item/l14465.html

    Can these be use to combine beams too?
    “Be who you are and say what you feel, because those who mind don't matter, and those who matter don't mind.” ― Bernard M. Baruch

    "They that can give up essential liberty to obtain a little safety deserve neither liberty nor safety."
    ― Benjamin Franklin; stairwell plaque in the Statue of Liberty

    "And so shines a good deed in a weary world." - Willy Wonka

    6 Steps To Prevent You From Getting SCAMMED On The Internet CLICK

  2. #2
    swamidog's Avatar
    swamidog is online now Jr. Woodchuckington Janitor III, Esq.
    Join Date
    Nov 2006
    Location
    santa fe, nm
    Posts
    1,545,276

    Default

    yes. as long as one beam is H-polarized and one beam is V-polarized.

    Quote Originally Posted by TechJunkie View Post
    Picked up one of these for 55% off. http://www.surplusshed.com/pages/item/l14465.html

    Can these be use to combine beams too?
    suppose you're thinkin' about a plate o' shrimp. Suddenly someone'll say, like, plate, or shrimp, or plate o' shrimp out of the blue, no explanation. No point in lookin' for one, either. It's all part of a cosmic unconciousness.

  3. #3
    Join Date
    Nov 2013
    Location
    State of Shock USA
    Posts
    608

    Default

    Awesome.

    Thanks again Dog.
    “Be who you are and say what you feel, because those who mind don't matter, and those who matter don't mind.” ― Bernard M. Baruch

    "They that can give up essential liberty to obtain a little safety deserve neither liberty nor safety."
    ― Benjamin Franklin; stairwell plaque in the Statue of Liberty

    "And so shines a good deed in a weary world." - Willy Wonka

    6 Steps To Prevent You From Getting SCAMMED On The Internet CLICK

  4. #4
    Join Date
    Mar 2006
    Posts
    2,478

    Default

    Is the 35 bucks including the 55% off? If so, maybe a good deal, but otherwise try to find out if the AR coatings and flatness of surface are as good as you can get for 35 bucks from sellers here. There may not be much in it, but there's only one way to find out short of buying both and doing more tests than most people ever want to.

  5. #5
    Join Date
    Nov 2013
    Location
    State of Shock USA
    Posts
    608

    Default

    No, it was 55% off $35, plus $6 priority flat rate shipping. $21.75 total.

    Quick question please. I just learned a little about wave plates. By little I mean little. I dont understand the formulas. Do I need one of these? In the past I've read that all you need to do is rotate each diode till they were polar opposites of each other. But from everything I've read here people use 1/2 wave plates to polarize one of the beams. Can you tell me in layman's terms what I'm missing here? Is rotation of the diodes wrong?

    If the cube doesnt work out I can always use it as a beam splitter and throw it into another project.
    “Be who you are and say what you feel, because those who mind don't matter, and those who matter don't mind.” ― Bernard M. Baruch

    "They that can give up essential liberty to obtain a little safety deserve neither liberty nor safety."
    ― Benjamin Franklin; stairwell plaque in the Statue of Liberty

    "And so shines a good deed in a weary world." - Willy Wonka

    6 Steps To Prevent You From Getting SCAMMED On The Internet CLICK

  6. #6
    Join Date
    Mar 2006
    Posts
    2,478

    Default

    Good price. No reason not to get it at that price, especially if it's surplus from better stock than usual. If nothing else, being broadband AR, you get to try it in any new situation before buying a more specilised one for size, wavelength, etc.

    About the waveplate, it rotates polarisation. You're right with the diodes but suppose you want to correct divergence in one axis for good far field, nice tight beam... You might use prisms or cylinder lenses, and do it after the PBS cube, so you need the beam's cross-sectional shape to to be the same for both diodes so they match. Normally (with single mode diodes, needing no correction after the PBS cube) you'd either rotate one diode to match the other (like in knife-edging combinations) or 90° offset from the other diode to do combination by PBS. Can't have it both ways! Until you use a waveplate! Now you can match the rotation of the diodes for equal corrections later, AND do the PBS combine because the plate rotates only the polarisation plane, not the beam shape.

    Very neat trick.

  7. #7
    Join Date
    Nov 2013
    Location
    State of Shock USA
    Posts
    608

    Default

    Got it!!! Thank you. I couldnt find a simple answer anywhere.

    Another piece to the puzzle that is my PJ.
    “Be who you are and say what you feel, because those who mind don't matter, and those who matter don't mind.” ― Bernard M. Baruch

    "They that can give up essential liberty to obtain a little safety deserve neither liberty nor safety."
    ― Benjamin Franklin; stairwell plaque in the Statue of Liberty

    "And so shines a good deed in a weary world." - Willy Wonka

    6 Steps To Prevent You From Getting SCAMMED On The Internet CLICK

  8. #8
    Join Date
    Jun 2010
    Location
    Australia
    Posts
    3,729

    Default

    Hey mate, yeah done this myself. Have fun!

    http://www.photonlexicon.com/forums/...-LPC-826-build
    This space for rent.

  9. #9
    Join Date
    Nov 2013
    Location
    State of Shock USA
    Posts
    608

    Default

    Quote Originally Posted by The_Doctor View Post
    Normally (with single mode diodes, needing no correction after the PBS cube) you'd either rotate one diode to match the other (like in knife-edging combinations)
    If the above statement is true then why are you using a waveplate Wayne? Aren't the LPCs single mode?

    Quote Originally Posted by dnar View Post
    Hey mate, yeah done this myself. Have fun!

    http://www.photonlexicon.com/forums/...-LPC-826-build
    “Be who you are and say what you feel, because those who mind don't matter, and those who matter don't mind.” ― Bernard M. Baruch

    "They that can give up essential liberty to obtain a little safety deserve neither liberty nor safety."
    ― Benjamin Franklin; stairwell plaque in the Statue of Liberty

    "And so shines a good deed in a weary world." - Willy Wonka

    6 Steps To Prevent You From Getting SCAMMED On The Internet CLICK

  10. #10
    Join Date
    Jun 2010
    Location
    Australia
    Posts
    3,729

    Default

    Quote Originally Posted by TechJunkie View Post
    If the above statement is true then why are you using a waveplate Wayne? Aren't the LPCs single mode?
    Their beam profile is not round or square still. LOL that build didn't stay like that for long. I also gave up using LPC as they kept giving up on me! Now using Optnext 638nm diodes that punch hard with a tight more visible beam. Even the camera picks up red better at this wavelength.
    This space for rent.

Posting Permissions

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