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Thread: WHAT IS THIS? Laser machine work DPSS assembly Please look at pic & description!

  1. #1
    Join Date
    Jun 2008
    Austin Texas since 1976

    Thumbs down WHAT IS THIS? Laser machine work DPSS assembly Please look at pic & description!

    Hello Mike, and other pl experts, I know you are probably busy men, and some ah sorry women,as well, but I think I need your mechanical, engineering, advice, experience skills, advice and help, oh and occasional depricating statements heh heh!.

    DPSS Assembly with Laser Diode, Nd:YAG Crystal, OC, HR

    My avatar has become a picture this assembly.

    I received this assembly last week and am looking at revamping it has some very nice machine work.

    It is as follows a steel block with an sdl 2462 T03 2 watt approximate 808nm diode.

    There is a pcb on the bottom of the transistor with a TEC and thermistor , some kind of phototransistor feedback mechanism, a shorting relay unfortunately I have none of it's original supporting circuitry.

    I have a small 20 turn pot adjustable little ebay die4drive? I think? 1.5amp. CW driwer, that at it's max IC could drive this diode to its max Ic 1.5A/?1watts ERP@808nm
    I am used to working with diodes that are much larger than this or a few mw.

    I have LTC1923 Linear Inc free engineering proto typing board a free sample from Linear Inc (very nice of them , no they will not send you same UNLESS you can convince of volume needs, Heh! Heh!, I hit both them and maxim, very nice folks!!!) for it's TEC control or a small Wavelength(Brand) TEC unit that is probably overkill, I think the LTC1923 can do like 3 amps at almost 5-6 volts maximum.

    I need to pull this thing out and make sure the diode is working and check ERP I have a good old coherent meter, I just bought a
    an Ophir 5 Watt ?or 20Watt smart head.

    Ok that said the diode has an overlapping block that has an approximate 1mm by 3mm grin rod in front of diode aperture on other side of block there as a 10-12 mm by same deep cylindrical hole in the bottom is a black o-ring spacing a YAG cylinder from direct contact there are three linear cuts in the hole sides at 120 degrees spacing, I assume some pieces of linear rope seal were installed at some point to hold the yag firmly,and prevent shifting of the mirrored YAG (1st resonator) surface.

    One or both faces of the 12X12mm approximatw YAG cylinder are finely polished and at least one AR coated and one is mirrored, I am guessing not sure which side up, and supposed to be forward as there are no pencil marked arrows on the YAG cylinder.

    Ok on the top of the cylinder is a plate that has a small about 2mm hole on top of this there is a round assembly with I believe is a brewster's mirror/ plate at 45 degrees offset AOI. I am unsure of it's correct orientation, it has 120 degree spaced screw holes on it, so there is 3 possible ways to mount it.

    OK out in front there is a cylindrical tube it has a 2mm hole though length there is a D shaped hole in side. There is a missing component from the laser that had fit into the hole from the side in the D shaped hole with flat side just below the linear hole, center of rounded side D shape, facing up to the top. It has 2 vertical downward screw holes that are drilled down into top of cylinder that descend into the missing component to have held it in place.

    Heres a clue There is a mini coax that is the right length to meet one edge of this D shaped cut out. A quick guess is a missing q-switch or AOM that might have held an lbo or ktp crystal I would say ktp because of lack of provision for any hermetic seal, or heating control circuit?

    Ok last but not least, the last short front cylinder section. It has a a mirror with a green appearance from its front. A test with a 5mw green laser transmitted at a diminished brightness in a small spot.
    There are 6 screw holes at 60 degree spacing 3 to mount onto the cylinder stack and 3 that are glued that apparently adjust the parallelism of the front mirror output coupler to the face of the mirrored surface of the YAG crystal.

    So questions are do I fire up as is and see if any 1064nm by replacing the output coupler mirror which is a filter for same this item could be an AOM modulated or qswitched 532nm laser with a missing KTP crystal holder combo aom for modulation control.

    I guess I could spray teflon or other anti-stick coat even fine machine oil in to the D shaped cavity and pull a wax, indium, lead, copper replica of same.

    I could get piece of copper and file to fit orfice ?

    I could simply just stick one of my twenty or so 2x3x3mm ktp or other size in the opening on a piece indium foil

    I was thinking of taking a copper electricians split bolt and setting a ktp in it with indium foil to space to right height setting the nut down on the split bolt and then filing off the top of the bolt at the right height to fit into the opening, then I guess I could use some silver epoxy to attach one or more resistors and a thermistor to form a ktp heater and feedback mechanism. Maybe instead just sticking a KTP on a small 6-10mm square peltier with a channel cut into some copper block around the KTP and some type of rubber gasket on top?

    I am totally unsure of the potential orientation between the existing YAG cylinder and brewsters mirror and an added KTP, as my only experience having being been between a diode YVO4 and KTP at a 45 degree off set like a stop sign.

    Your opinions are greatly appreciated this assembly obviously is not your average Chinese machine work but was part of some carefully engineered USA or similar workmanship.The seller is abundantly technically proficcient and has a spectrometer claims no knowledge of its original intended application.

    The grin rod lens has a small scratch I have a bag of these that are similar size but are for I assume these are for 1550nm.

    The SDL 2462 might be toast if so I will replace with a 2 watt fleabay offering for $95, unless someone knows of a better or cheaper T03 style diode.

    I know little about the brewster's mirror and it's proper intended function, and correct proper orientation, as to how it should be oriented to 1 of 3 possible choices.

    If I am not mistaken this mirror will help to suppress multimode operation and can act to polarize output of the YAG rod, as it has a lot of random scattering inside.

    I recognize this as a great hurdle on any homemade green or 1064nm dpss laser project the machine work is beautiful even though it is missing most of its screws. It is going to need a die4 drive modulatable driver in the end.

    I may want to return to operation in a 1064nm mode since I have some very nice continuum laser 20mm shg type 2 heated LBO ovens, a tech at Continuum Lasers Inc. said 50mw or so of 1064nm would produce some green output if the 24 vdc to the LBO heater was connected and if the pump spot nice and small.

    Any suggestions and ANYONE that could help me pull a mold of orfice or locate an aom/qswitch for it would be really sweet.
    Last edited by frank_1257; 10-27-2008 at 22:55. Reason: numerous typos dyslexia!!!!
    clicking on my avatar will show the tricolor photocoagulator resonator cavity from a Lumenis Varia eye surgery medical laser, which i am attempting to refit. It originally was designed to produce 50-1500mw of 532 / 50-600mw of 659nm / 50-600mw of 561nm (Yellow)
    Clicking on my Avatar will show a picture of the inside of this cavity with a 1cm bar diode in the first of 3 OEM postions & KTP holder.
    Caviar Dreams on pennies, well lots of pennies.

  2. #2
    Join Date
    Nov 2007
    Cairns, Australia


    Just a tip, that picture isnt link, its a directory on your computer, you need to upload it to somewhere like imageshack then post the link it gives you ....

  3. #3
    Join Date
    Feb 2010
    Melbourne, Australia


    It would be really good to be able to find that picture here for reference purposes.

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