Advances in the spectral coverage of tunable continuous-wave optical parametric oscillators

We discuss principles, design challenges, performance highlights as well as current limitations of state-of-the-art widely tunable continuous-wave optical parametric oscillators sought to be practical for implementation as turn-key systems. Employing a flexible two-stage design concept that can be adapted to several single-frequency laser pump sources, we demonstrate how a wavelength range from 450 nm up to 3500 nm can be covered almost seamlessly. Emerging keyapplications in the realm of quantum technology, like fundamental studies of novel color centers in diamond, are presented in an illustrative manner.