Investigation of Stimulated Polariton Scattering from the B 1 -symmetry Modes of the KNbO 3 Crystal

Stimulated polariton scattering from the B1-symmetry modes of a KNbO3 crystal to generate a terahertz wave (THz-wave) with a noncollinear phase-matching scheme is investigated. The frequency-tuning characteristics of the THz-wave by varying the phase-matching angle and pump wavelength are analyzed. The expression for the effective parametric gain length under the noncollinear phase-matching condition is deduced. Parametric gain and absorption characteristics of the THz-wave in KNbO3 are theoretically simulated. The characteristics of KNbO3 for a terahertz parametric oscillator (TPO) are compared to those of MgO:LiNbO3. The analysis indicates that KNbO3 is an excellent optical crystal for a TPO, to enhance the THz-wave output.