Trace of conversion for a weak CW field: the original field (dark blue), at about \(~3000\) counts per temporal bin (166 ps), the signal depleted in the presence of the pump (light blue) and the converted idler (red). At the center of the gate, at the peak power of the pump pulse, we observe a depleted signal of \(~17\) cps over a \(0.6 \) ns window, and estimate \(\eta = 99.4(?) \%\). Noise levels amount at less than \(2 cps\) per time bin.