中文摘要：

针对太赫兹波光学参量效应中增益介质对太赫兹波强烈吸收的特点,提出光学参量效应中泵浦光、斯托克斯光和太赫兹波三波共线相互作用可以有效放大太赫兹波。以周期极化铌酸锂晶体为例,通过解耦合波方程,在不同的近似条件下分析了前向和后向太赫兹波的放大特性。计算结果表明,在太赫兹波吸收系数远大于太赫兹波增益系数的条件下,泵浦光、斯托克斯光和太赫兹波三波共线作用可以有效提高太赫兹波功率。分析结果对周期极化铌酸锂晶体光学参量振荡产生太赫兹波的实验研究提供深入和全面的理论基础。

英文摘要：

Collinear interaction of pump wave, Stokes wave and terahertz wave was proposed in this letter to solve the problem of intense absorption of terahertz wave in gain medium in terahertz parametric oscillation. The amplification characteristics of forward and backward terahertz wave were theoretically analyzed by solving coupled wave equations under difference approximate conditions based on PPLN crystal as an example. The results indicate that the terahertz wave power can be greatly enhanced by the collinear interaction of the pump wave, the Stokes wave and the terahertz wave as the absorption coefficient are greatly more than the gain coefficient of the terahertz wave. The analysis results in this letter provide comprehensive theoretical foundations for the experiment researches of terahertz wave parametric oscillation in PPLN crystal.