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Thread: my lasers

  1. #11
    Join Date
    Aug 2010
    Location
    Hungary
    Posts
    221

    Default Next Project 8W 520nm

    My next project.
    8X NDG7475 (G2 )
    Lasertack mounts+ right angle prisms
    OPTLaser optics
    Prism pair correction
    DT-50B galvo
    S4 panel , TEC cooled diodes.
    I've measured the raw power of 4 diodes.
    It's 2.5W @ 1A (panel meter reads 0.1010V means 1A )
    I didn't go higher lack of the proper cooling and limit of my Laserbee.
    Click image for larger version. 

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    Some pictures from the progress of build.
    Attached Thumbnails Attached Thumbnails DSC00001.JPG  

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  2. #12
    Join Date
    Feb 2007
    Location
    Fort Mill, SC USA
    Posts
    1,507

    Default

    Looks good! How long did alignment take? My alignment efforts always take longer than I think it should . .

    -David
    "Help, help, I'm being repressed!"

  3. #13
    Join Date
    Aug 2010
    Location
    Hungary
    Posts
    221

    Default

    Ditto....
    I need a full weekend to align an RGB at least.
    Sometimes i have to realign the optics because of the tense of the screws + other things . Warming and cool downs can do tricky things on this sensitive system.
    Knok-knock i didn't have to realign for 4 months now.

  4. #14
    Join Date
    Aug 2010
    Location
    Hungary
    Posts
    221

    Default

    I would like to ask many experienced laserists:
    How much is the prism pair loss on 2X or 3X magnitudoes?
    I've measured 25% on 2X and 38% on 3X
    The prisms mounting template is from Lasertack (just like Zoof template)
    Prisms are from Rob for 520 nm

  5. #15
    Join Date
    Feb 2008
    Location
    Northern Indiana
    Posts
    921

    Default

    I have never used a prism pair on the green diodes. I know on the P73 the losses are high due to the polarization. A waveplate before the prisms could help on the greens like it does on the reds. Worth a shot.

  6. #16
    Join Date
    Jun 2007
    Location
    Monroe, Mi USA
    Posts
    818

    Default Prism Pair NOT a good choice

    Quote Originally Posted by epyn View Post
    I would like to ask many experienced laserists:
    How much is the prism pair loss on 2X or 3X magnitudoes?
    I've measured 25% on 2X and 38% on 3X
    The prisms mounting template is from Lasertack (just like Zoof template)
    Prisms are from Rob for 520 nm
    Hate to tell you....but your 25% and 38% optical power loss is typical when using a Prism Pair !!!
    To reduce the beam astigmatism.... Drop the PP and go with a 6X set of Cylindrical Lenses....and suffer about 2~4% loss.

    VERY nice build !!!!

    CDBEAM
    Beam Axiom #1 ~The Quantum well is DEEP ! Photons for ALL !!
    .
    Beam Axiom #2 ~Yes...As a matter of fact...I DO wear tinfoil on my head !!
    .
    Beam Axiom #3 ~Whe'n dout...Po ah Donk awn et !!
    .
    Beam Axiom #4 ~A Chicken in every Pot, and a Laser Lumia in every Livingroom !!
    .
    Beam Axiom #5 ~"Abstract Photonic Expressionism"....is "Abstractonimical" !!
    .
    Beam Axiom #6 ~ "A Posse ad Essea" ~ From being possible to being actual ...is the beam target !

  7. #17
    Join Date
    Aug 2010
    Location
    Hungary
    Posts
    221

    Default

    I hate to accept that loss is typical.

    I know the advantages on CYL and my RGBs are corrected by them.

    I'm working now horizontally stacked beams to get high power green so CYL can't be used.

    Click image for larger version. 

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    Lightspace has the same template for their Green -and Blue as well- and using prisms.

    Click image for larger version. 

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  8. #18
    Join Date
    Aug 2010
    Location
    Hungary
    Posts
    221

    Default

    Quote Originally Posted by logsquared View Post
    I have never used a prism pair on the green diodes. I know on the P73 the losses are high due to the polarization. A waveplate before the prisms could help on the greens like it does on the reds. Worth a shot.
    I have the polarization rotator because of the PBS.
    I don't measured the crossed beams on PBS(that doesn't requires rotator or WP) but i've already measured the raw beam without any optics .
    Got high loss in any ways.
    I think no optics help me out even a rotator/WP
    Prisms are lossy.Have to accept.
    With no any correction these NDG7475 diodes have incredible bad divergence so i sacrifice the power for benefit of quality.
    Anyways it will be an 8W green. There is much power to loss from.
    Last edited by epyn; 05-25-2019 at 03:05.

  9. #19
    Join Date
    Jun 2007
    Location
    Monroe, Mi USA
    Posts
    818

    Default Some options

    Well....I have had just GREAT results lately with coupling the NDG7475 with the new G8 Collimation lens from DTR. The 7475 starts out having a lower degree of astigmatism....than say the NUB044 or P73 LD....so... it needs somewhat less correction.

    Now....this new lens is GREAT.....as it removes all Ghost Box artifacts from the 7475.....and....for whatever reason.....seems to somewhat correct the beam.

    SO.....try this lens out !!!! Easy trial !! Low cost...Then....you MAY need less prism magnification....and therefore less power loss.

    OR....although an added mechanical arrangement....take your entire Knife Edge assembly...rotate it 90 degree.....To do so... mount it on an Ally bracket ( Call this a.... Rotation Bracket ). In that way....you go from Horizontal stackage….to Vertical stackage...and then propagate into your Cyl. lenses in the working
    orientation.

    I would do the LD mount/Knife edge alignment procedure...with the Rotation Bracket unmounted from the main optical platform....so you are not working against gravity. Once the beams are at the optimal Beam/Beam/Beam/Beam alignment....then mount the Rotation Bracket.

    Good luck,
    CDBEAM
    Last edited by CDBEAM; 05-25-2019 at 06:38.
    Beam Axiom #1 ~The Quantum well is DEEP ! Photons for ALL !!
    .
    Beam Axiom #2 ~Yes...As a matter of fact...I DO wear tinfoil on my head !!
    .
    Beam Axiom #3 ~Whe'n dout...Po ah Donk awn et !!
    .
    Beam Axiom #4 ~A Chicken in every Pot, and a Laser Lumia in every Livingroom !!
    .
    Beam Axiom #5 ~"Abstract Photonic Expressionism"....is "Abstractonimical" !!
    .
    Beam Axiom #6 ~ "A Posse ad Essea" ~ From being possible to being actual ...is the beam target !

  10. #20
    Join Date
    Aug 2010
    Location
    Hungary
    Posts
    221

    Default

    I give the shot for G-8 lens .
    Thank you for the information!

    Ferenc

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