Independently tunable, dual-wavelength source based on two-crystal, continuous-wave, singly resonant optical parametric oscillator

The paper presents a novel and generic approach for the generation of two truly independently tunable wavelengths, which are unbound by energy conservation and can be independently controlled to provide any arbitrary value using a simple design based on a compact four mirror ring cavity continuous wave optical parametric oscillator (OPO). Both wavelengths are resonant within the same cavity, thus providing high circulating intensities at the two wavelengths, and the beams can have the same power. Such a novel system can be used to generate tunable terahertz radiation down to 0.55 THz.