[Yuhang, Eleonora]

The green production depends on incident power and on the crystal temperature. We need to find the best temperature to have the best phase matching and maximize the green production. The measurement was performed from 5.794 to 7.787kOm, which corresponds to 312.976K to 304.767K.

The method we used is to change the p-pol beam to s-pol. In this case, we can lock OPO with this beam and at the same time have green production, since only s-pol produces green beam. In transmission of OPO, we put a dichroic mirror which reflects infrared light and transmits green. The reflected beam is focuse with a lens on the  Qubig PD used for the locking,  while the transmitted beam is focused with a lens on a  InGas PD.

The attached picture shows the green production as a function of the temperature. We see two peaks: the largest is at 306.8437 K, the second largest is at 309.3391 K.

 The IR input power was 141 mW.   At the optimal temperature (309.3391 K), we measure a the green power of 0.277 uW  while the IR trasmitted power is 0.189 mW . (Tramsmissivity:  0.13%.  Lower than that measured few days ago #elog 999)