Extended mode-hop-free tuning by use of a dual-cavity, pump-enhanced optical parametric oscillator

We report extended mode-hop-free tuning in a continuous-wave, pump-enhanced optical parametric oscillator (PE-OPO). We employ a dual-cavity configuration to allow independent control of the resonant pump and signal fields, and so we can suppress frequent mode hops in the signal as the pump is tuned in frequency. With the signal field clamped in frequency by an uncoated etalon, the idler field can be scanned smoothly through a range of 10.8 GHz. The PE-OPO outputs can also be tuned coarsely from 1.01 to $1.18 \mathit{\mu }\mathrm{m}$ in the signal and from 2.71 to $3.26 \mathit{\mu }\mathrm{m}$ and 4.07 to $5.26 \mathit{\mu }\mathrm{m}$ in the idler. We find that increased idler absorption only slightly increases the oscillation threshold.