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Thread: Need some advice howTo combine beams ;)

  1. #1
    Join Date
    Jan 2005
    Location
    Norway
    Posts
    1,302

    Default Need some advice howTo combine beams ;)

    Ok..
    I got :

    Blue
    Green
    Dual RED
    (DPSSL with analog modulation)

    My first problem is to combine the 2 red modules PERFECT with my BQ :roll:
    Then mount all 4 lasers perfectly into one nice white line !!!

    today after some... eh... 2.3.4.5 hours with testing and playing
    I discoverd that this is NOT gonna be easy :twisted:


    Any advice?
    What do I need, steel, alu, wood, mounts, mirror ?

    Thanx for all help




    And THANX to SPEC for shipping me this EXTREMLY nice blue unit
    And THANX to Chuck and Max for the lovely red laser units

  2. #2
    Join Date
    Feb 2005
    Location
    Florida
    Posts
    802

    Default

    Ah,, You got em...kewl

    Well , I've marked each laser V and H polarization
    And also marked the Beamsplitter with an H and V to correspond
    to each laser input..
    If you reverse these,, bad things can happen , like backreflections
    and possibly blow out the diode..
    Hence the reason for marking the cube..
    The arrow pointing away is the beam output.

    First thing of course is to mount them like junktronix did :
    http://photonlexicon.com/forums/viewtopic.php?t=415

    Use of a Newport MM-1 or P100-P or a Thorlabs KMS is suggested for the cube..
    I use either a Thorlabs KM05 with 1/2" mirror or KM100 with 1" mirror for the other.

    With H laser going straight thru ., then use a mirror on an adjustble mount
    to aim the V laser into the cube V side.
    Or, You could do it the hard way and just point each laser into the appropiate sides (very hard to adjust this way) and hope you are patient.

    I think from there you can figure it out how to make them overlap at beam exit and at the spot...FUN
    "My signature has been taken, so Insert another here"
    http://repairfaq.ece.drexel.edu/sam/laserfaq.htm
    *^_^* aka PhiloUHF

  3. #3
    Join Date
    Jan 2005
    Location
    Norway
    Posts
    1,302

    Default

    yes I did figure out that I can adjust one beam with adjusting the beamqube
    But my idea was to not add that mirror... (Becouse i dont have any mirror mounts)

    If I manage to adjust the 2 red beams into ONE with only adjusting the bq it will be OK..

    But anyway.. It seems like i have to buy mounts with fine adjusting..


    Then my biggest problem is to aim each laser perfectly into the Thrico !!
    Becouse adjust the laser up\down at one end and turn it is not the correct way to do it..
    To mix the 3 lasers I need to adjust it UP\down at the front and up\down at the back at the same time


    This is gonna be a pain in the ass !!
    I consider maybe buy a filters to use, one for the blue and one for the green.



    Junktronix: That optic table you got there was damn nice !
    What about selling that complete to me ?

  4. #4
    Join Date
    Mar 2006
    Location
    Massachusetts
    Posts
    194

    Default speaking of

    Where can I pick up a cuple of beam combiner/splitters?

  5. #5
    Join Date
    Feb 2005
    Location
    Florida
    Posts
    802

    Default

    liteglow:
    It is so much easier to align by using the mirror.
    You wont have to move the modules around much this way.
    I know . Ive tried almost every combination out there..

    I am going to build a few plates up that one can add the red modules to .
    And offer them to the folks here so a Mirror mount and BS mount can also be added too.
    Now you see why I am building a combined unit all in the same box

    DjDevNull:
    PM me., I may have a few extra BeamSplitters laying around
    "My signature has been taken, so Insert another here"
    http://repairfaq.ece.drexel.edu/sam/laserfaq.htm
    *^_^* aka PhiloUHF

  6. #6
    Join Date
    Jan 2005
    Location
    Norway
    Posts
    1,302

    Default

    I need mirror mounts in EXPRESS SPEED

    To sad I live in Norway... so there is loong waiting to get the lasers.. then galvos.. then software..

    Then I need mirror mounts, and that is some new weeks with waiting
    It`s pretty hard to sit here and watch my 4 lasers with a power of 800mW total..
    And not be able to use them :evil:

    And the laptop with 100.00 colorful ildaframes is sitting there and waiting also...

  7. #7
    Join Date
    Jan 2005
    Location
    Norway
    Posts
    1,302

    Default

    ok, this is not going anywhere :?

    I need to buy mounts !! and I need it fast..
    Who have some to shipp me ? some in the EU?

    Who do I contact if I want to buy?



    thanx

  8. #8
    Join Date
    Aug 2005
    Location
    Silicon Valley
    Posts
    416

    Default

    I don't think you'll be able to get your system aligned by adjusting the position of the laser sthemselves. Here is exactly how I aligned mine:

    - mount the green laser and aim it into the scanners. Shim the heat sink so that the beam is parallel to the breadboard (this is important) and the beam is hitting the X mirror in exactly the right spot. This is your "reference" beam and you'll be aligning all the others to be perfectly in line with it.
    - mount the blue laser and shim it so that the beam is hitting the pass green/reflect blue dichro at the same height as the green beam. Position the dichro so that the green and blue beams are hitting it at the same position on opposite sides. Adjust the dichro mount so that the combined beams are in exactly the same place. You'll have to project the beam at least 20-30 feet away to get the alignment perfect. I had to slightly move my scanners at this point since my green+blue dichro is about 3mm thick and offsets the beam a bit.
    - Combining the 2 red beams really is going to require a few adjustable mounts. I set up the laser going through the cube first and aligned it into the green+blue beam. Then I mounted the cube so that the red beam was passing through the very center and adjusted the tilt / rotation so that it was exactly parallel with the beam (get the waste beams to be exactly the same height above the breadboard). Next, mount the 2nd red laser and use the adjustable mirror to get it aimed into the center of the cube. The 2 red beams need to hit the splitter surface in the middle of the cube at exactly the same place. Adjust the cube so that the waste beams are lined up and then adjust the mirror for the 2nd laser so that the 2 beams are aligned at 20-30 feet away.

    I use the word "exactly" a lot didn't I? That's because if you want your beams to be alined for any distance, they need to be accurate to a few miliradians (same scale as the divergence of the lasers) There is no way to do this without some precision adjustable mirrors (IMHO).

    The type of aluminum breadboard I used is fairly easy to find on eBay, but not cheap. Mine is 3/4" thick which is overkill, but very very stiff so it stays aligned. I have a 12" x 24" x 3/4" breadboard here that I'd sell for $250.

    I have a bunch of MM1 mirror mounts that I can sell for $25 each or $35 with a small dielectric mirror (99% reflectivity versus 94% for aluminum). I have some MM2's here also, but they're probably bigger than you need. If you tell me how high you want the center of the mirror to be, I'll see if I have suitable L-bracket mounts here also. I used Newport post mounts which are nice if you have a box full of them, but expensive if you're buying them for the project.

    I am still trying to find a good source for beam combining dichros and polarizing beam splitter cubes. I have a bunch of RGB color wheels from DLP projectors here. I'll check the performance at 45 degrees and if they look like they'll work, I'll offer them to PL people for cheap.

  9. #9
    Join Date
    Jan 2005
    Location
    Norway
    Posts
    1,302

    Default

    Junktronix:
    Great !!
    That mirror mounts is the same as on your pictures ?

    Well... i think i will ned 3-4 maybe more is better

    And if you have any L bracket I take them !!!
    The height YOU find is the height I will USE

    I will use my alu-baseplate to mount the stuff on !

    So give your TOTAL $ include shipping to Norway ! (Global Express Mail EMS)
    And I pay you TODAY


    Cheers..

  10. #10
    Join Date
    Aug 2005
    Location
    Silicon Valley
    Posts
    416

    Default

    I checked the RGB dichros in the DLP color wheel and they are way better than I thought. I can't figure out a way to put a table here so check my web site for the performance chart:

    http://junktronix.com/DLP-RGB.htm

    I would recommend combining the same way as my RGB projector

    - combine green (pass) with red (reflect) using the green filter
    - combine red/green (pass) with blue (reflect) with the red filter

    The filter wheels look like this:



    They'll need cleaning which is easy since the dichro coatings are tough and difficult to scratch. I use ispropyl and lens cleaning tissue. The filters are glued onto the wheel. I mark them with a carbide tipped scribe and they snap right off. For PL members, $15 each plus shipping ($4.05 Priority Mail in the US)

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