Laser amplification

[clamport]

Hello all,

I'm relatively new to lasers but I love playing with new things. I recently came across a shop that was offering Erbium laser rods for a pretty decent price, and I was wondering what kind of amplification power something like this would give?

I love tinkering, and I was curious specifically about the power of the laser it could produce with 15 focused 350 mW IR laser diodes. Is the additional power per cost efficiency a worthwhile investment?

Thanks!
Chris

 

[diachi]

Hello all,

I'm relatively new to lasers but I love playing with new things. I recently came across a shop that was offering Erbium laser rods for a pretty decent price, and I was wondering what kind of amplification power something like this would give?

I love tinkering, and I was curious specifically about the power of the laser it could produce with 15 focused 350 mW IR laser diodes. Is the additional power per cost efficiency a worthwhile investment?

Thanks!
Chris

It won't give any amplification power.

You're not going to have an output any greater than your input, so 15*0.35=5.25W input to get <5.25W (significantly less in practice) output at a different wavelength. You would also need optics to collimate or focus both the pump beams and the output beams as well as mirrors to form a resonator. Not to mention designing/buying/building the mounting hardware.

An example of the efficiency you can expect - ~120W at 808nm side pumping a 3mmx65mm 0.6% doped Nd:YAG rod would yield maybe ~50W at 1064nm. That's 42% optical efficiency - electrical efficiency is even worse at around 14-15%. I'm not sure how efficient Er doped rods are, but it'll be around those figures.

 

[Alaskan]

Looks like a huge project to pull that off, better to just buy a surplus diode pumped ND YAG.

Chris

 

[ultimatekaiser]

Yeah, unless it's something exotic, or you want the challenge, building a pulsed rod laser is too expensive to generally be worth it. Er and Nd YAGs are best pumped with flash lamps, or with very powerful diodes in a highly reflective chamber that is flood cooled with water often times. They're very expensive to make, so buying a premade one can be cheapest with patience and a lot less frustration. Don't want to spend too much time reinventing the wheel. I have a cth:yag, which might warrant building due to its uniqueness, but common YAGs may or may not be worth it unless you are well equipped.

 

[diachi]

Yeah, unless it's something exotic, or you want the challenge, building a pulsed rod laser is too expensive to generally be worth it. Er and Nd YAGs are best pumped with flash lamps, or with very powerful diodes in a highly reflective chamber that is flood cooled with water often times. They're very expensive to make, so buying a premade one can be cheapest with patience and a lot less frustration. Don't want to spend too much time reinventing the wheel. I have a cth:yag, which might warrant building due to its uniqueness, but common YAGs may or may not be worth it unless you are well equipped.

Easier to buy one of those ready built units from China and whack some mirrors on each end if you're going down the DIY YAG route. Cooling taken care of, diode arrays built in, all that nice stuff.

That's the way I'd do it unless I had about $10,000 sitting spare to have the components made. A pump chamber alone can be expensive, never mind the CNC machined parts, which will probably be one offs, and then all of the optics.

 

[Alaskan]

The longer i live the more i wish i had a cnc mill

 

[diachi]

The longer i live the more i wish i had a cnc mill

As well as a 3D printer and a laser cutter. Would make life much easier.