[Help] Building a green DPSS laser

[erickes]

Hello guys, I'm new in the forum, my name is Erick.
I'm building a Green DPSS laser for my final project, what I need help is if the parts I'm buying are the correct ones, I recently bought the Nd:YAG crystal and the KTP one, I'm looking forward to buy the laser diode and I found this one on ebay:

808 nm 2W
808nm 810nm 2000mW 2W TO3 Package Infrared IR Laser Lazer Diode LD | eBay

I need help deciding what driver should I buy, I found this one on ebay, and seems capable of driving up to 3 A and can be modulated, which is desirable , the driver is the next one:

3A Laser Driver
3A Analog Linear PWM Laser Diode Driver with Thermal Protection | eBay

Does that driver going to be good for the diode? I also have 2 other diodes of the same mount(TO-3) but with 1W power, can the driver also meet the requirements for those other 2 also?
Ok, seems a lot of questions but I wanna build the laser in the right way(without blowing some expensive stuff). Also searched for heatsink for the laser diodes and found these ones:

Inner diameter 13mm Cooling Heatsink/Heat Sink for Laser Diode Module

2pcs TO3 Transistor Heat Sinks to 3 Black Amuminum 45x45x14mm | eBay

Should one of them or both be capable for just testing the laser diodes?

Well, that's pretty much what I need to know, I really appreciate the help and thanks in advance for it!

 

[diachi]

Hello guys, I'm new in the forum, my name is Erick.
I'm building a Green DPSS laser for my final project, what I need help is if the parts I'm buying are the correct ones, I recently bought the Nd:YAG crystal and the KTP one, I'm looking forward to buy the laser diode and I found this one on ebay:

Need some more details about your crystals and project in general. What coatings are on the crystals? Did you get any other required cavity optics? How are you mounting the crystals? KTP really works best when you have active temperature control (TEC works well). Active temperature control for the diode is advised too. Are you correcting the pump beam from the diode? Raw output from these diodes is terrible - you want a nice tight spot in the middle of your Nd:YAG/YVO4.

808 nm 2W
808nm 810nm 2000mW 2W TO3 Package Infrared IR Laser Lazer Diode LD | eBay

I need help deciding what driver should I buy, I found this one on ebay, and seems capable of driving up to 3 A and can be modulated, which is desirable , the driver is the next one:

3A Laser Driver
3A Analog Linear PWM Laser Diode Driver with Thermal Protection | eBay

Does that driver going to be good for the diode? I also have 2 other diodes of the same mount(TO-3) but with 1W power, can the driver also meet the requirements for those other 2 also?
Ok, seems a lot of questions but I wanna build the laser in the right way(without blowing some expensive stuff). Also searched for heatsink for the laser diodes and found these ones:

Yes - that driver should work fine. This seller also has good drivers if you want another source: tomorrowssystem | eBay



Inner diameter 13mm Cooling Heatsink/Heat Sink for Laser Diode Module

2pcs TO3 Transistor Heat Sinks to 3 Black Amuminum 45x45x14mm | eBay

Should one of them or both be capable for just testing the laser diodes?

That should do for a quick test but you really want active cooling for the diode too - I.E. a TEC.

Well, that's pretty much what I need to know, I really appreciate the help and thanks in advance for it!

Some more details about your project would help us help you further ... plus I'm just interested - always good to see a DIY DPSS build, not many people even try them - especially not with discrete Nd:YAG/KTP crystals.

Arguably the best open/free resource on the internet for DIY DPSS lasers: Sam's Laser FAQ - Home-Built Diode Pumped Solid State (DPSS) Laser

 

[erickes]

Some more details about your project would help us help you further ... plus I'm just interested - always good to see a DIY DPSS build, not many people even try them - especially not with discrete Nd:YAG/KTP crystals.

Arguably the best open/free resource on the internet for DIY DPSS lasers: Sam's Laser FAQ - Home-Built Diode Pumped Solid State (DPSS) Laser

Hey thanks for your answer, like I said recently bought this Nd:YAG crystal:
New Casix ND YVO4 ND GDVO4 ND YAG 1064nm Laser Crystals for Research Coated | eBay
The number 19 to be specific , the coating level it's 1.3%, and it's coated like this: coated S1 HR R>99.8%@1064 & HT T>95%@808,S2 AR R<0.1%@1064 & HR R>99%@532.

I was also looking at Sam's FAQ and seems to be a great site for info about this DPSS projects , but I'm new into this field of optics, so I was looking for some extra help,and found this great site. About the output beam , I was looking forward to use a lens to focus the beam to impact the Nd:YAG first I want to see the 1064nm output, I hope it's as easy as it seems.

Again thanks for your answer!

 

[diachi]

Hey thanks for your answer, like I said recently bought this Nd:YAG crystal:
New Casix ND YVO4 ND GDVO4 ND YAG 1064nm Laser Crystals for Research Coated | eBay
The number 19 to be specific , the coating level it's 1.3%, and it's coated like this: coated S1 HR R>99.8%@1064 & HT T>95%@808,S2 AR R<0.1%@1064 & HR R>99%@532.

I was also looking at Sam's FAQ and seems to be a great site for info about this DPSS projects , but I'm new into this field of optics, so I was looking for some extra help,and found this great site. About the output beam , I was looking forward to use a lens to focus the beam to impact the Nd:YAG first I want to see the 1064nm output, I hope it's as easy as it seems.

Again thanks for your answer!

You need an OC (Output Coupler) for the 532nm as well when the time comes - should be HT@532nm and HR@1064nm. You'll want plano-concave (Hemispherical configration). If you are just going for 1064nm just now you'll need an OC for that too - partial reflect (PR) @ 1064nm. I'd probably opt for hemispherical again for that. Adjustable mirror mount required in both cases.

Your final layout will look something like the top left on this diagram once you add the KTP:

An adjustable mount for the KTP is desirable too. Some details on that on the Sam's FAQ page. May be able to fabricate that yourself!

You'll need safety glasses for 532nm, 808nm and 1064nm. If you want to "see" the 1064nm you'll probably need an IR visualizer card for 1064nm - CMOS cameras won't see 1064nm - CCD might but they are not at all sensitive at that wavelength. CCD cameras without an IR filter will see 808nm just fine - although it's only just barely visible to the eye - seriously, 18W@808nm isn't even as bright as 1mW@650nm.

Read through that Sam's FAQ page and then read it again.

A half decent LPM is good to have too.

What other laser/optics experience do you have?

 

[erickes]

You need an OC (Output Coupler) for the 532nm as well when the time comes - should be HT@532nm and HR@1064nm. You'll want plano-concave (Hemispherical configration). If you are just going for 1064nm just now you'll need an OC for that too - partial reflect (PR) @ 1064nm. I'd probably opt for hemispherical again for that. Adjustable mirror mount required in both cases.

Your final layout will look something like the top left on this diagram once you add the KTP:

An adjustable mount for the KTP is desirable too. Some details on that on the Sam's FAQ page. May be able to fabricate that yourself!

You'll need safety glasses for 532nm, 808nm and 1064nm. If you want to "see" the 1064nm you'll probably need an IR visualizer card for 1064nm - CMOS cameras won't see 1064nm - CCD might but they are not at all sensitive at that wavelength. CCD cameras without an IR filter will see 808nm just fine - although it's only just barely visible to the eye - seriously, 18W@808nm isn't even as bright as 1mW@650nm.

Read through that Sam's FAQ page and then read it again.

A half decent LPM is good to have too.

What other laser/optics experience do you have?

Hey thanks for the reply, its been a long time and I'm stuck in this project!, It is been really hard to get a green output, I think the problem is the output of the diode and also the mounts of the crystal , the Nd:YAG mount specially , i could adapt a piece of aluminum to get the crystal as possible to the diode , but looking at the output in a spectrometer couldn't see a 1064 nm lasing output, I could really use any advice, I read a lot of information in Sams FAQ, I was searching for commercial mounts for the crystals but couldn't find anything , Im looking to buy another diode with more power do you think of any seller or product that has better output than the chinese one?
Thanks for the help and answer in advance

 

[Alaskan]

Although you may have already spent money on other stuff, I think your project would go much faster with less head ache if you bought this to start with: Second Harmonic 532nm Vanadate Nd:YVO4 Green KTP Laser Crystal Optics, YAG : Nd | eBay

This listing is for New Old Stock High Power Laser Optics Crystals Assembly manufactured by VLOC company consisting of neodym vanadate, Cristal Laser KTP second harmonic crystal and system of HR mirror and output coupler deposited onto crystals sides. In more details the assembly consists of Optically Contacted Neodym Vanadate Nd:YVO4 (2,75% Nd+++) laser crystal and Second Harmonic Green KTP Non-linear Optical Crystal (5x5x2mm size) cut to generate the second harmonic of YAG:Nd 1064nm main lasing line. Potassium Titanyl Phosphate crystal is cut for NCPM (non-critical phase matching) 532nm (Theta = 90deg, Phi = 23,5deg).

Optically contacted crystals are used for higher power lasers unlike glue contacted crystals where the glue is burning under intense irradiation power. The crystal assembly is rated upto 0.5W of power for continuous green 532nm line depending on cooling efficiency. The output power of green light for this assembly depends on efficiency of cooling and pumping power. One way to get a good power is to use a thin Indium foil with small pinhole (about 1mm in diameter) as the heat conductor and to mount the vanadate crystal to the metal heat spreader directly without intermediate substrate. I will include a small piece of Indium foil for free with this crystal assembly.

The other way to increase the maximum output power of crystal stack is to mount vanadate crystal in a way that it should be attached to some optically transparent heat conductive substrate like quartz glass, sapphire etc. and then attached to the metal heat spreader like shown on the last picture (commercial laser assembly). We managed to get about 350mW of green power with 2.7W of 808nm pumping power (quartz mounting substrate) and more than 520mW with 3.9W of pumping power (sapphire substrate). The other types of transparent substrates may be used like GaN, garnets, optical ceramics etc.

 

[diachi]

There's a thread somewhere on those crystal assemblies ... Couple people bought them and managed to get some green out IIRC.

 

[Alaskan]

"some" does not sound encouraging.

 

[diachi]

"some" does not sound encouraging.

Think this is the thread...

https://www.photonlexicon.com/forum...ion-of-a-discussion-from-the-Big-Green-Thread)

Ends up getting some decent green output (Check post #28).

This thread is also worth a read:

The Big Green Thread (I'm gonna regret posting this in the morning))

This thread too:

http://laserpointerforums.com/f45/do-yourself-complete-green-dpss-o-like-crystals-42495.html

Pictures aren't working, maybe if you fire the address into the wayback machine.

Edit: Yep, pictures work if you use the wayback machine: https://web.archive.org/web/2016080...omplete-green-dpss-o-like-crystals-42495.html

 

[Alaskan]

I am probably going to buy one of those vanadate and KTP crystalsmyself, seems much easier than what ericky is planning.

 

[H2Oxide]

I am probably going to buy one of those vanadate and KTP crystalsmyself, seems much easier than what ericky is planning.

Much easier but also much less flexible.

Monolithic DPSS crystals are the absolute best way to build your first DPSS, but if you want to do anything with the output they're not really viable. (Much better configurations come pre-assembled and for less money)

Depending on what erickes is trying to accomplish, microchip may or may not be the way to go. If he's just going for some green photons, then this would probably be the best way to do it, but if he's actually trying to do something inside the cavity (like learn about the actual physics behind the whole set up) then obviously that won't work with a single crystal.

Erickes, what are the specs on the OC you're using? How is it being mounted? Is the KTP properly phase-matched? Do you have any pictures of your set up? More info is needed.

 

[Alaskan]

Maybe erickies didn't write down his forum password? Might not be back, I don't know.