We demonstrate that it is possible to obtain a mid-infrared optical frequency comb (OFC) experimentally by using a continuous-wave-pumped optical parametric oscillator (OPO). The comb is generated without any active modulation. It is based on cascading quadratic nonlinearities that arise from intra-cavity phase mismatched second harmonic generation of the signal wave that resonates in the OPO. The generated OFC is transferred from the signal wavelength (near-infrared) to the idler wavelength (mid-infrared) by intracavity difference frequency generation between the OPO pump wave and the signal comb. We have produced a mid-infrared frequency comb which is tunable from 3.0 to 3.4 µm with an average output power of up to 3.1 W.
- parametric oscillators
- self-action effects
- nonlinear optics
- nonlinear wave mixing
Ulvila, V., Phillips, C. R., Halonen, L., & Vainio, M. (2014). High-power mid-infrared frequency comb from a continuous-wave-pumped bulk optical parametric oscillator. Optics Express, 22(9), 10535-10543. https://doi.org/10.1364/OE.22.010535