报道了一种基于环形腔结构的种子注入式太赫兹参量振荡器的运转特性, 非线性晶体为MgO∶LiNbO3, 太赫兹波采用垂直表面耦合的输出方式, 斯托克斯环形腔由3个腔镜和MgO∶LiNbO3晶体的全反射面构成。抽运源为调Q脉冲激光器, 其输出波长为1064.2 nm, 脉冲宽度为7.5 ns。当抽运脉冲能量为105.5 mJ、斯托克斯光输出镜的透过率为20.1%时, 获得的太赫兹波脉冲能量使得示波器的输出电压为3.3 V, 对应的斯托克斯光脉冲能量为16.1 mJ, 抽运脉冲能量阈值约为10 mJ。在相同的抽运条件下, 将基于环形腔结构的种子注入式太赫兹参量振荡器、种子注入式太赫兹参量产生器与环形腔结构的无种子注入式太赫兹参量振荡器的输出能量和抽运脉冲能量阈值进行比较。结果表明, 基于环形腔结构的种子注入式太赫兹参量振荡器具有较高的输出能量及较低的抽运脉冲能量阈值, 当抽运脉冲能量较小时, 其在输出能量方面的优势更明显。

Operation characteristics of an injection-seeded terahertz parametric oscillator based on ring-cavity configuration are reported. The nonlinear crystal used in the experiment is MgO∶LiNbO3. The terahertz wave is emitted perpendicularly to the output surface. The Stokes ring-cavity is constituted by three mirrors and total reflection surface of MgO∶LiNbO3 crystal. The pumping source is a Q-switched laser, whose output wavelength is 1064.2 nm and pulse width is 7.5 ns. When the pumping pulse energy is 105.5 mJ and the transmittance of the Stokes wave output coupler is 20.1%, the maximum terahertz pulse energy output leads to the output voltage of 3.3 V, and the corresponding Stokes pulse energy is 16.1 mJ and the pumping energy threshold is about 10 mJ. Under the same pumping conditions, the output energy and pumping pulse energy threshold of the injection-seeded terahertz parametric oscillator based on ring-cavity configuration and injection-seeded terahertz parametric generator are compared with that of a ring-cavity terahertz parametric oscillator without seed injection. The results show that the injection-seeded ring-cavity terahertz parametric oscillator based on ring-cavity configuration has higher output energy and lower pumping energy threshold, and the oscillator has more obvious advantage in energy output when the pumping energy is smaller.