Tunable Backward THz-Wave Parametric Oscillation Using a Periodically Poled Lithium Niobate

We demonstrated tunable backward terahertz-wave parametric oscillation using a slant-stripe-type periodically poled lithium niobate with a poling period of 53 μm. A novel noncollinear phase-matching scheme, quasi-collinear phase-matching condition, produces the wide tunability.