Breakthroughs in Photonics 2012: Breakthroughs in Optical Parametric Oscillators

The latest breakthroughs in optical parametric oscillators (OPOs) for the generation of tunable coherent radiation from the continuous-wave to femtosecond timescales are presented. Advancement of novel device concepts, development of phase-coherent and broadband frequency combs, and expansion of wavelength coverage of OPOs to new limits toward the visible and mid-IR are the main focus of the review.