decan an 808 and add a DPM?

[chaosfourever]

So it was said that one can decan a 1w 808nm and add a cheap DPM from a cheap chinese green laser to get a high power green pointer. Has anyone done this or can someone post some info and pictures about this?

 

[JLSE]

So it was said that one can decan a 1w 808nm and add a cheap DPM from a cheap chinese green laser to get a high power green pointer.  Has anyone done this or can someone post some info and pictures about this?

Have a look atthe link in my sig... Its not exactly what you are requesting, but may help

 

[GooeyGus]

Yup... those glued crystal assemblies are an entire lasing cavity as one unit. Add 808 and you're done, just need to collimate after that.

If you want more power, collimate the 808 such that the beam waist is in the center of the Nd:YVO4

 

[.3lite]

Yup... those glued crystal assemblies are an entire lasing cavity as one unit. Add 808 and you're done, just need to collimate after that.

If you want more power, collimate the 808 such that the beam waist is in the center of the Nd:YVO4

I don't think so, several crystals use to have "their max power" at different points, but anyway, that crystal nd:yvo4+ktp in green laser today times are really sux, I believe it's max power input of about 500mW, no more.

 

[ElektroFreak]

^ you can get DPMs in varying sizes that accept pump powers up to a watt or so.. The DPM in a 5 - 20mW green pointer probably won't accept more than 500mW, that is true, but the DPM from a 200-250mW pointer should be able to accept considerably more pump power. Also, you can overdrive just about any crystal to a certain degree before it burns up..

 

[JLSE]

I dont think ive ever burned up a crystal but rather the coatings. The more power you feed in to them, means you better be able to remove the heat.

In the first labby build that I did, the beam went from mode to mode, but this problem was solved simply by applying more pressure to the mount via the screws. Go too far and you crack them, use enough pressure and it draws off the heat faster. Heat seemed to be the only issue, the crystals themselves were able to handle the input with no problems..

 

[ElektroFreak]

^What size was the DPM you used?

 

[GooeyGus]

[quote author=GooeyGus link=1240424407/0#2 date=1240458232]Yup... those glued crystal assemblies are an entire lasing cavity as one unit. Add 808 and you're done, just need to collimate after that.

If you want more power, collimate the 808 such that the beam waist is in the center of the Nd:YVO4

I don't think so, several crystals use to have "their max power" at different points, but anyway
[/quote]


I DO think so. I'm not talking about the face of the crystal. I'm talking in 3D here. You want the focal point of the laser to be "inside" (if that makes more sense for you) the vanadate. It's hard to do since the vanadate on those glues assemblies is so thin, but that will get you the most power. It's all about pump beam energy density inside the lasing medium. :

 

[JLSE]

^What size was the DPM you used?

IIRC, 2.5 - 3mm W x 4mm L x 2mm H  Very chunky ;D Wrapped in indium foil, which made all the difference. Without the indium, there was too many mode issues.

 

[chaosfourever]

so if i use a DPM from a 20mw then i should use 500mw of 808nm to get 500mw of green?

 

[ElektroFreak]

so if i use a DPM from a 20mw then i should use 500mw of 808nm to get 500mw of green?

No. The process of converting the 808 to green is only about 20-30% efficient at best. That means that on a good day you'll typically see 100-150mW of green for 500mW of 808 pump power.

 

[Cyparagon]

You want the focal point of the laser to be "inside" (if that makes more sense for you) the vanadate. It's hard to do since the vanadate on those glues assemblies is so thin, but that will get you the most power. It's all about pump beam energy density inside the lasing medium.  :

Why not stop with a high energy density in just the middle? Is there any reason (besides heat) that one can't just have an extremely beefy pump with the focal point after the vanadate (or before)?

 

[GooeyGus]

[quote author=GooeyGus link=1240424407/0#7 date=1240507285]You want the focal point of the laser to be "inside" (if that makes more sense for you) the vanadate. It's hard to do since the vanadate on those glues assemblies is so thin, but that will get you the most power. It's all about pump beam energy density inside the lasing medium.  :

Why not stop with a high energy density in just the middle? Is there any reason (besides heat) that one can't just have an extremely beefy pump with the focal point after the vanadate (or before)?[/quote]

Maybe I'm not quite understanding what you mean, but the more energy density you get inside the lasing medium (vanadate./yag) the more 1064nm lasing you will get. This is not as much of an issue with green, but for peak power it's still how it should be. For example, in a 473nm laser you can pass 3W over the entire surface of the yag and not get any output at all. Now, when you collimate the pump beam such that the beam waist is in the yag, you all the sudden get blue out. Same goes for green, you'll get much more 1064 (and therefore much more 532) if your pump beam comes to a waist inside the YVO4.

Now, if what you're saying is to just use raw power over the whole face of the crystal, (which I think you are   ) yeah that will work too! But, take all that power and focus it into the vanadate and you'll get even more green as long as you dont put burns in the coatings on the back of the crystal lol...


Also... you guys are referring to these little crystal cavities as "DPMs". What does that stand for?? Obviously diode pumped something or other...

I've always heard them reffered to as MCA's  (multiple crystal assemblies)


Also, there's no need to de-can your pump diode... just put the crystal assembly in front of it. Find a super short focal length lens and focus the pump into the assembly (this is how most high powered green pens are built)

 

[ElektroFreak]

I think DPM means "diode-pumped microchip" laser.. could be wrong tho.

edit: Yep.. here's a link that lays it out: http://www.casix.com/product/prod_opt_laser_dpm.html

 

[.3lite]

[quote author=chaosfourever link=1240424407/0#9 date=1240512649]so if i use a DPM from a 20mw then i should use 500mw of 808nm to get 500mw of green?

No. The process of converting the 808 to green is only about 20-30% efficient at best. That means that on a good day you'll typically see 100-150mW of green for 500mW of 808 pump power.[/quote]

Show then those crystals which have that effectivity, never saw such crystals, never in green pointers f. example from ebay, so let's say ten percent.

@topic
So all you can get from 500mW is about 60-50mW, which means about ten percent of effectivity, it's quite good, but remember, if you pump more you get better effectivity.

Anyway, here's two of my crystals, one from green laser today (it was said 50mW I believe) and the second which propably can hold 2W+- of input power.

 

[JLSE]

[quote author=ElektroFreak link=1240424407/0#10 date=1240515425][quote author=chaosfourever link=1240424407/0#9 date=1240512649]so if i use a DPM from a 20mw then i should use 500mw of 808nm to get 500mw of green?

No. The process of converting the 808 to green is only about 20-30% efficient at best. That means that on a good day you'll typically see 100-150mW of green for 500mW of 808 pump power.[/quote]

Show then those crystals which have that effectivity, never saw such crystals, never in green pointers f. example from ebay, so let's say ten percent.

@topic
So all you can get from 500mW is about 60-50mW, which means about ten percent of effectivity, it's quite good, but remember, if you pump more you get better effectivity.


In reference to the pics above.. Size doesnt matter, the crytal sets in leadlight pointers are huge compared to DX pointers, but funny enough, the DX pointer put out more light.
[/quote]

10% if your using absolute junk, or crystals that  arent aligned properly to the pump. 30% is not hard to achieve at all. 30% can be done with the crystals tight against an open can pump, and like Gooey stated above, focusing the pump into the medium will yeild even more. The only problem with optics in between the pump and medium is that it is easier to burn the crystals up... which I have found out the hard way :-/