WANTED: Plano-Convex Lens Coated for IR

**300EVIL** · 02-28-2009, 16:01

I need a PC lens coated for around 808nm for focusing the stripe output on my large Coherent laser diode. It needs to be around 40mm to fit the output. focal length is not too important but something around 6 inches would be good.

I bought one on ebay but it's crap and is obviously some factory reject.

Here are some pics of the laser I want to focus.

**MechEng3** · 02-28-2009, 16:18

IMHO you need a big honkin cylinder lens to get the thing close to being a spot. I have some round lenses here and a few larger units A/R coated...let me look and see what I have. What is the motive here? Crystal pumping for SHG? Or just sheer diode brute force?

**300EVIL** · 02-28-2009, 16:59

Hey MechEng!

Yeah, I eventually want to use it as a pump diode for frequency doubling a YAG but I'm just looking to focus the beam down for burning stuff right now.

I want to see if I can get this sucker to cut steel.

Let me know if you have anything that would work. Also, Any advice you can give me on turning this thing into 10-30W of 532nm would be greatly appreciated. I was thinking about side pumping a yag rod since the beam is a stripe but maybe focusing and pumping a yag cube would be the way to go.
Thanks!
Adam

**MechEng3** · 02-28-2009, 17:34

Yes side pumping will result in the best yield of input power conversion. I would consider a Z fold cavity with external mirrors. I have a KTP here somewher that will do good in that project...I could cut you a rod to length but I am afraid the dopant level may be a little low. Let me see if I have any of the 3mm X 65mm rods. They were supposed to be around 1% doped. A focal point to burn with? If you could find an off axis parobolic mirror....PM me with your mailing addy ...I have a few things that you may find very usefull.

**Laser Ben** · 02-28-2009, 17:57

EEK! Is that wire thick enough!? I would use 10 gauge or at least 12...

**300EVIL** · 02-28-2009, 18:15

Originally Posted by MechEng3

Yes side pumping will result in the best yield of input power conversion. I would consider a Z fold cavity with external mirrors. I have a KTP here somewher that will do good in that project...I could cut you a rod to length but I am afraid the dopant level may be a little low. Let me see if I have any of the 3mm X 65mm rods. They were supposed to be around 1% doped. A focal point to burn with? If you could find an off axis parobolic mirror....PM me with your mailing addy ...I have a few things that you may find very usefull.

OOOH! Sounds interesting!

Thanks for the great info. I'll send you a PM!
Thanks!

Originally Posted by Laser Ben

EEK! Is that wire thick enough!? I would use 10 gauge or at least 12...

Pictures are deceiving. That is in fact 10 gauge wire.

Although, I did try running 2 16 gauge wires per leg for the initial test and they did get very hot.

I'm uploading video of the laser in action on youtube right now. Should have it up on PL soon.
Thanks!
Adam

**Xytrell** · 02-28-2009, 18:22

Three gauges down is double the copper volume, so four 16AWG = 10AWG

**300EVIL** · 02-28-2009, 19:05

Originally Posted by Xytrell

Three gauges down is double the copper volume, so four 16AWG = 10AWG

Ah, Okay, thanks for that mathematical equation. Good info!

Here is the video of the laser in action.... http://photonlexicon.com/forums/show...4986#post84986

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