Efficient laser-pumped parametric oscillation at terahertz using doped LiNbO/sub 3/

During the past few years, terahertz (THz)-wave generation and detection have gained increasing interest from both the fundamental and applied points of view. We have recently demonstrated an efficient THz wave generation by introducing the Si-prism output coupling method into a LiNbO/sub 3/ optical parametric oscillator (OPO), which exhibits multiple advantages such as coherency, wide tunability, relatively high power (more than 10 mW at the peak), and compactness of its system (tabletop size). This scheme is based on the laser light scattering from the lowest A/sub 1/-symmetry polariton mode of LiNbO/sub 3/. Wide continuous tunability is easily obtained by changing the angle between the pump beam and the resonator axis, due to the noncollinear phase-matching condition. In the report, we describe the THz-OPO using doped LiNbO/sub 3/ (LiNbO/sub 3/:MgO) which exhibits much better performances than conventional undoped LiNbO/sub 3/ OPO.