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Thread: DIY multiwatt 532nm?

  1. #1
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    Default DIY multiwatt 532nm?

    There is a nice 25W 808nm pump diode on ebay, fiber coupled to 600um fiber.
    If one were interested in constructing a 532nm resonator cavity for this unit, what is the simplest setup that could be used? Could the crystals have intrinsic HR/AR coatings, or would one have to use separate HR/OC mirrors?
    Just curious about this and trying to learn more about high power NLO resonator construction.

    Here's a beginner's attempt after reading some sam's pages:

    fiber termination-coupling lens through 1064HR mirror into ND/KTp, to vanadate, to 808/1064HR 532LR to output optics.
    TEC cooling and temperature regulation is understood and no problem, same with the diode power supply.
    Last edited by drlava; 03-14-2008 at 15:45.

  2. #2
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    Have you seen this project?
    http://www.showlaser.dk/backstage/projects/

    That guy has put a lot of thought in to this:
    "For the 532nm laser, the setup will be a V-fold, using a thin disk Nd:YVO4 crystal as the lasing medium. The thin disk will have a broadband HR coating on the back side, and will have that side soldered directly to a copper heat spreader, that is soldered to a TEC, that is mounted on a heatsink.
    The Thin disk will be pumped by a fiber coupled 808nm diode bar. The light from the fiber will be collimated and focused on the thin disk. The pump light that is not absorbed by the nd:yvo4 crystal will be reflected off the back side of the thin disk crystal, and out of the thin disk, where it will be re-collimated, reflected and focused back onto the thin disk for another pass, to get the highest level of efficiency.. "

  3. #3
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    [QUOTE=drlava;46232]

    fiber termination-coupling lens through 1064HR mirror into ND/KTp, to vanadate, to 808/1064HR 532LR to output optics.
    [QUOTE]

    DR this bit does not make sense The ND is the vanadate (or YAG) they are ND doped to produce the 1064 light.
    You would go fiber termination-coupling lens through 1064HR/808AR mirror into Vanadate (though this could be HR1064/AR808 coated - some of the larger square chunks will be so you may not need the first mirror you refer to) then through KTP (AR coated) and then to OC which will be HR808 HR1064 HT532
    this will form a standard end pumped cavity though may not be ideal configuration for this level of pump power.

    Rob
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  4. #4
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    I have seen that too tried to email him no response about sourcing the thin disk vanadate material. I have pump lasers by spectra physics, optopower and coherent in 25-70 watts and a nice linear supply good for 0-7.5vdc at up to 100amps , have gotten my $350 set of nice goggles with flip up add on filters, I have an assortment of various commercial mount heaters KTP of 3 sizes, various YVO4 , yag rods small ones various mirrors and optics I want to do exactly what the showlaser.com guy has planned but it would seem that I will have to talk castech into selling me some thin coated YVO4 they have asked about size???? I am not real sure other than I have learned that thickness should be smaller than spot size, castech has answered my emails yesterday but I need more info from some one in the know like dimensionality and dopant levels that are ideal for the pumping range I have. I think I will call newport on friday or monday to research fiber lens that I should use. I may try something really crude to get first laser off ground until I get right fiber lens like using 2x 500watt quartz bulbs to build an air cooled yag cavity and use that to supply 1064 to my vanadate.

  5. #5
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    I saw a open verdi 2 watt head on ebay I was blown away by compact size and simplity of design.

  6. #6
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    Quote Originally Posted by dar303 View Post
    Have you seen this project?
    http://www.showlaser.dk/backstage/projects/

    That guy has put a lot of thought in to this:
    "For the 532nm laser, the setup will be a V-fold, using a thin disk Nd:YVO4 crystal as the lasing medium. The thin disk will have a broadband HR coating on the back side, and will have that side soldered directly to a copper heat spreader, that is soldered to a TEC, that is mounted on a heatsink.
    The Thin disk will be pumped by a fiber coupled 808nm diode bar. The light from the fiber will be collimated and focused on the thin disk. The pump light that is not absorbed by the nd:yvo4 crystal will be reflected off the back side of the thin disk crystal, and out of the thin disk, where it will be re-collimated, reflected and focused back onto the thin disk for another pass, to get the highest level of efficiency.. "
    I believe this is how the jenlas lasers do it
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  7. #7
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    Default 532nm

    "I have seen that too tried to email him no response about sourcing the thin disk vanadate material."

    I bought mine from seller 1220elina from Hungary. Here was one of his previous auctions:

    http://cgi.ebay.com/ws/eBayISAPI.dll...m=320241043693

    He also sells crystals for red, blue and green. He sent me a little paper with some explanation of how to build a thin disk laser. If anyone wants it let me know.

    One thing builders need to be aware of is the wavelength matching of the nd:yag crystal. ie. your laser diode needs to be exactly 808nm. The absorption peak falls off dramatically past this.

    A lot of people on ebay list diodes as 808nm, or high power pump for DPSS, but have they really checked it?
    Don't jump in and buy a diode without making sure, or your money is wasted.

    One thing I am trying to figure out about the thin disk lasers, is what coatings are required on the KTP. All of my KTP has coatings DBAR 1064/532. However I think that the required coatings should be Side 1 AR 808 HR 532, Side 2 AR 532 HR 808.

    I have seen other journal articles about building single frequency nd:yvo4/KTP 532nm lasers that use the birefringence of the nd:yvo4 to force the cavity to oscillate in single mode. And for this the above coatings we needed. Does anyone know if they are needed for the thin disk lasers?

  8. #8
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    Quote Originally Posted by hologeek View Post
    "I have seen that too tried to email him no response about sourcing the thin disk vanadate material."

    I bought mine from seller 1220elina from Hungary. Here was one of his previous auctions:

    http://cgi.ebay.com/ws/eBayISAPI.dll...m=320241043693

    He also sells crystals for red, blue and green. He sent me a little paper with some explanation of how to build a thin disk laser. If anyone wants it let me know.

    One thing builders need to be aware of is the wavelength matching of the nd:yag crystal. ie. your laser diode needs to be exactly 808nm. The absorption peak falls off dramatically past this.

    A lot of people on ebay list diodes as 808nm, or high power pump for DPSS, but have they really checked it?
    Don't jump in and buy a diode without making sure, or your money is wasted.

    One thing I am trying to figure out about the thin disk lasers, is what coatings are required on the KTP. All of my KTP has coatings DBAR 1064/532. However I think that the required coatings should be Side 1 AR 808 HR 532, Side 2 AR 532 HR 808.

    I have seen other journal articles about building single frequency nd:yvo4/KTP 532nm lasers that use the birefringence of the nd:yvo4 to force the cavity to oscillate in single mode. And for this the above coatings we needed. Does anyone know if they are needed for the thin disk lasers?
    You are the BEST I feel that Castech can make me anything I want and probably are already selling multiunit product to many buyers but when contacted they acted like they were going to have to do a Custom order I am guessing wanting thousands for said items, I see these auctionare going higher that I would like if you read into the auctions they state you will need other components so it sucks bidding against others who see a picture of a complete laser head but still at under $250 I will take it anyway I can get it. Thank You Very Much Happy Fourth I am about to get a small inheritance and look foward to producing 10 or more watts of 532 and 473 well at least 5 of that. If pigs had wings they could fly and so I hope can I!!!!!!!!!!!!

  9. #9
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    Quote Originally Posted by hologeek View Post
    "I have seen that too tried to email him no response about sourcing the thin disk vanadate material."

    I bought mine from seller 1220elina from Hungary. Here was one of his previous auctions:

    http://cgi.ebay.com/ws/eBayISAPI.dll...m=320241043693

    He also sells crystals for red, blue and green. He sent me a little paper with some explanation of how to build a thin disk laser. If anyone wants it let me know.

    One thing builders need to be aware of is the wavelength matching of the nd:yag crystal. ie. your laser diode needs to be exactly 808nm. The absorption peak falls off dramatically past this.

    A lot of people on ebay list diodes as 808nm, or high power pump for DPSS, but have they really checked it?
    Don't jump in and buy a diode without making sure, or your money is wasted.

    One thing I am trying to figure out about the thin disk lasers, is what coatings are required on the KTP. All of my KTP has coatings DBAR 1064/532. However I think that the required coatings should be Side 1 AR 808 HR 532, Side 2 AR 532 HR 808.

    I have seen other journal articles about building single frequency nd:yvo4/KTP 532nm lasers that use the birefringence of the nd:yvo4 to force the cavity to oscillate in single mode. And for this the above coatings we needed. Does anyone know if they are needed for the thin disk lasers?
    Dear hologeek, I am far from an expert yet but your KTP is not going to need to receive any 808nm pumping that is the job of your vanadate to produce 1064nm from 808nm so it would if extracavity as in the showlaser.com v fold example, you would probably want a HR@808nm to stop any stray 808nm on side 1, you would want AR@1064, HR@532 as well on side 1. Now I am a little green on this or hopefully soon Ha! Ha! LAL. You would I believe want a HR @1064, AR@532 on the side 2. OK that said if you were going to place both crystals in a cavity and end pump the vanadate, then if I am not mistaken your cavity optics can be created between side one of your YVO4 with a AR@808nm HR@1064 on side one and AR @1064, ?AR@808nm for multiple pump passes through vanadate. Now on your KTP you would want AR@1064 for pumping it and AR@808 to pass through KTP (I think?) on side one , and AR@808nm AR@1064 on side 2. Then you would want a concave/plano lens to rebound light and make a cavity mirror you would want HR@808, HR@1064 and AR@532 then you would want a output coupler lens and a filter to redundantly block the escape of any 808/1064. I am very green at this there is more than one way to skin a kitty depending on whether end or v-fold pumping your YVO4 and whether you are using side 1 of the YVO4 and side 2 of the KTP as cavity mirrors, keep in mind that in a optical cavity you ideally want to rebound the light between two mirrors/ which can be a coating, with one being almost 100% reflective and the other being partially reflective around 80-90% so the laser light can escape. Better to read through SAM's laser FAQ's then to listen to a Dyslexic such as my self, as the, I Quote " Difficulty of performing a given task is directly proportional to a persons capability for confusion" Mine being high! My regards From Frank

  10. #10
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    Quote Originally Posted by frank_1257 View Post
    You are the BEST I feel that Castech can make me anything I want and probably are already selling multiunit product to many buyers but when contacted they acted like they were going to have to do a Custom order I am guessing wanting thousands for said items, I see these auctionare going higher that I would like if you read into the auctions they state you will need other components so it sucks bidding against others who see a picture of a complete laser head but still at under $250 I will take it anyway I can get it. Thank You Very Much Happy Fourth I am about to get a small inheritance and look foward to producing 10 or more watts of 532 and 473 well at least 5 of that. If pigs had wings they could fly and so I hope can I!!!!!!!!!!!!
    I would also like to state that short of buying a laser that is spec by the mfg. at 808nm at 77 deg f or 25 deg c the normal suggested operating temperature of most laser diodes., that having access to a very expensive spectrometer would be in order. I personally am going to go with my fiber laser and power supply/TE cooler in hand to the University of Texas at Austin, and do some begging. I was thinking if you had a suitable power meter and a pump laser that was supposed to be in the 808nm range that you could pump a YVO4 crystal that had a AR@808nm, HR@1064 on side one, AR@808nm, AR@1064 on side 2 and place a concave/plano lens that was HR@808, AR@1064 in front like a YAG lens and maybe a redundant filter in front. Now if you had as I will a fiber laser with a thermister that is supposed to be 10K ohms at 25 deg cent I would start off with it cooled down and slowly back off my peltier current the whole time observing my power output at 1064nm as it peaked I would simply record my thermisters resistance or setpoint of my TE controller.
    This would be the optimal temperature to tune my laser to if I did not achieve 1064nm power levels that were suggested for my size pump and crystal match the diode or module would be considered worthless and a paypal not as described complaint or redundant ideally credit card chargeback would ensue. The best pumping efficiency is going to be achieved with +/-3nm centering of laser diode/module to 808nm anymore than 5nm and the conversion efficiency is going to fall like a rock. Many sellers of fiber lasers on ebay are selling as suitable for 808nm pumping when these packages are really only good for engraving marking and medical applications but not pumping YAG or YVO4 they just want to move items so buyer beware! Cavet Emptor

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