Sourcing vanadate rods, non-standard dimensions

[NobleGas]

As per my other thread, I need to replace an Nd:YVO4 rod from my engraver's laser head. The original rod is diffusion bonded with a 2mm long undoped YVO4 section, bonded to a 10mm long doped section at probably 1.1% as this seems to be the most common. The face dimensions are 4 x 4mm.
Many manufacturers list stock rods of 3x3mm and a lot of manufacturers offer custom rods; my enquiries so far have effectively been 'how many thousands do you want', in as much as after replying that I only need 1 to 3 items (so spare plus an extra in case of accidents), it all goes quiet.

I am considering if a 3mm square section rod could be used, but I am concerned about the power levels; the rod is mounted in a cut out in a copper heatsink with indium foil for heat transfer; I could add copper shims of 0.5mm on all 4 sides to deal with the cooling problem, but I am mainly concerned about the damage thresholds; the laser is end-pumped with 30W of 808nm and is Q switched, producing peak powers of 20kW at 1064nm, according to the rating plate. Would this be excessive for a 3x3 rod?

[mixedgas]

Find your local lapidary club. A friend who does lapidary slab sawed some Yellow ND:YAG for me. Cost was 25$ for the rough rectangular stone.

Buy a surplus rod of the right length, Let the factory x-ray orient , polish and coat it the cavity facing sides.

Sawing it down and polishing the sides for the pump was child's play for my friend.

Put a thick soft soft polymer coating that may dissolve in a solvent (Dopping Wax, First Contact, Beeswax, Pitch) over the optical coatings.

With the right hobbyist setup it took him about an hour to slab out two nice sized rectangular rods and put optical grade parallel faces and one pump

Lapidary folks love ND:YAG and ND:VANADATE melt scrap for gems.

I was hoping for an intracavity RAMAN shift from the extra doping.



Steve