Sheila, Nutsinee Terry & Haocun

We revisited the crystal position (alog43292) as our ~22mW threshold is inconsistent with the 8mW indicated in alog41150.

We followed the procedure in alog43292: We measure nonlinear gain by injecting a seed beam, scanning the seed phase, and measuring the de-amplification and amplification of the seed.  (x=(sqrt(max./min)-1)./(1+sqrt(max./min)); gain=1./(1-x).^2;)

The plot with a sinc² fitting is attached and with a SHG fiber launch power of 18.3 +/-0.1 mW and a seed launch power of 2.7 mW the phase matching temperature seems to be ~33.8 C. The pump power is limited by the fibre power limit.

The dual resonance position was set to within about +/- 10 clicks on the translation stage driver so the temperature accuracy is still not much better than 0.1C as in alog41150.

We left the crystal at the position where we see co-resonance for 33.8 C, because we think this is about at the peak of the phase matching curve.