铌酸锂晶体中参量振荡产生高功率可调谐太赫兹波的实验研究

Experimental Investigation of High-Power Tunable THz-Wave Parametric Oscillator Based upon MgO:LiNbO_3 Crystal

利用一块大体积MgO：LiNbO3晶体,采用浅表垂直出射方式构成太赫兹（THz）波参量振荡器（TPO）,实现了高功率可调谐的THz波输出,调谐范围为0.8-2.8 THz。当抽运功率密度为197.4 MW/cm^2时,在1.73 THz处每个THz脉冲的最大输出能量为173.9 nJ,对应的能量转换效率为2.2×10^-6。实验过程中观察到了一阶和二阶斯托克斯（Stokes）光,一阶Stokes光相对于抽运光的频移等于产生的THz波的频率。

High-power nanosecond pulsed terahertz（THz）-wave radiation is achieved via a surface-emitted MgO：LiNbO3 terahertz parametric oscillator（TPO）.THz-wave radiation from 0.8 THz to 2.8 THz is obtained.The maximum THz-wave output is 173.9 nJ per pulse at 1.73 THz while the pump power density is 197.4 MW/cm^2.The corresponding energy conversion efficiency is 2.2×10^-6.During the experiments the first-order and the second-order Stokes waves are observed.The frequency shift of the first-order Stokes wave is equivalent to the frequency of generated THz-wave.