中文摘要：

设计了一种新型的表面辐射内腔太赫兹波参量振荡器,交叉谐振腔结构允许增益介质放置在泵浦光谐振腔内,使用浅表垂直辐射结构能够从铌酸锂晶体中有效耦合输出太赫兹波。推导了在太赫兹波参量振荡器中非共线相位匹配条件下有效参量增益长度的表达式。大的泵浦光尺寸和长的增益介质长度能增加有效参量增益长度。在有效参量增益长度表达式的基础上推导了太赫兹波参量振荡器的阈值表达式,在不同的参数条件下理论分析了谐振腔阈值表达式。大尺寸泵浦光、低频太赫兹波、短谐振腔腔长、斯托克斯光高反射率输出镜、长增益介质能有效降低太赫兹波参量振荡器阈值。文中的阈值分析对太赫兹参量振荡器的实验研究有参考价值。

英文摘要：

A novel surface-emitted intracavity THz-wave parametric oscillator（TPO） was designed to improve the down-conversion efficiency.An intersecting cavity geometry was employed that allowed the nonlinear medium to be placed within the cavity of the pump laser.The surface-emitted scheme was employed to extract the THz-wave from MgO：LiNbO3 crystal.The expression of the effective parametric gain length under the condition of noncollinear phase matching condition was derived.The pump beam with larger radius and the crystal with longer length could increase the effective parametric gain length efficiently.Based on the expression of the effective parametric gain length the expression of TPO oscillation threshold was deduced and was theoretically analyzed under different conditions.Larger beam radius of pump wave,lower frequency of THz-wave,shorter cavity physical length,higher reflectivity of the Stokes output coupler and longer crystal length can effectively reduce the oscillation threshold.Such an analysis is useful for the experiments of TPO.